If you don’t feel like reading everything I’ll just post shorter to read “runes” in the middle and at the end there are some various ideas. So if you wanna read my reasoning you can read the entire post or just get the basics by reading the “runes” part.
Intro and Reasonings
Feral druids are in a weird spot at the moment. I personally think their damage is kinda fine. But with the way every class works right now with insane rune abilities we are somewhat lagging behind. I think the main culprit for this is our rune Savage Roar. It is an ability that needs to be used to even consider doing ANY reasonable damage. It is a mandatory rune and ability. That is the first issue with it. The second is that we have to spend way too many Combo Points on it which invalidates most other finishers. That these finishers are only doing lukewarm damage is another issue but I think the Savage Roar issue needs to be solved first. What does it matter how much/little damage Rip and Ferocious Bite does if we barely get to use them? In a Gnomeregan run I can count the number of FB I get to use on one hand. And when I use it it most often does less damage than a Mangle or Shred…
Savage Roar
So first and foremost something needs to be done about Savage Roar. I suggest turning it into a passive or semi-passive.
It could just be a flat +30% damage while in cat form. Or have a short ramp-up time where your attacks increase damage done by 5% for 30 seconds up to 6 stacks (30%). With one auto-attack per second and abilities it should reach 30% in roughly 4 seconds. Other classes have gotten similar runes (both passive and with a sort of ramp-up) so this isn’t some far-out-there idea.
30% extra damage passively sounds super OP but let’s be honest here, it only brings Feral cats up to a baseline level where many other dps specs already were before SoD.
It is a pretty dull rune in the sense that it doesn’t “add” anything to the spec.
So my real suggestion is to bake the effect into a passive effect on our Wild Strikes rune instead. Crazy right?!? But bear with me. Pun intended. 
Wild Strikes and Survival of the Fittest
Wild Strikes is another of those mandatory runes to use. Rather than having two mandatory runes we now get one. That opens up the leg slot for something more fun and engaging. Like a new finisher. Something that interacts with our bleeds, perhaps?
I dislike saying “that class has this so we should also get this.” But we can use Hunters as an example of how Wild Strikes has a major design flaw. Hunters get 10% extra stats on their Heart of the Lion rune along with the raid-wide buff. It has a personal effect along with the raid effect so that it shouldn’t feel too bad when they’re forced to run it in a raid/party over any other rune. And if there are two Ferals in the group only one needs to use Wild Strikes, but at the same time there is nothing else to use so one of the Ferals gain 0 from their Chest rune.
HotL is a raid-wide effect and Wild Strikes is party-wide so they aren’t exactly similar but the principle holds.
Wild Strikes also have the issue of being mandatory for bear tanks and that is also an issue that I think needs to be solved. It will be partially solved when we go to 20+ raids cause right now there just isn’t room or need for more than one Feral druid in a 10-man raid. But that “solution” is a pretty awkward one and I think most bears will be forced to run Wild Strikes either way. And let’s be frank, the extra damage, threat and rage they gain from the extra attacks is really really useful.
That is a harder nut to crack and not really within the scope of this post as this focuses more on cats. A small suggestion to make Survival of the Fittest more attractive would be to give it a party-wide effect of say 5% less damage taken. So in encounters where there is a lot of damage the bear can forgo the extra damage for the group to opt for more survivability. It is by no means a perfect solution and might very well end up being useless. Or have the rune also provide a new ability that is like a Power Word: Barrier or Divine Sacrifice type thing.
Wild Strike/Windfury I think needs to be toned down in general. It should not be what makes or breaks melee classes. Maybe have it proc from just white attacks? No Hamstring/Wing Clip spam for WF procs. But that is also beyond the scope of this post. Just food for thought.
PvP
A side-effect of putting the Savage Roar effect on Wild Strikes would be the inability to pick up SotF (some baseline survivability as cats are rather squishy) for PvP and get the +30% damage. But you’d also get the choice of the interrupt Skull Bash or the new finisher for PvP. You want the damage or the interrupt. Even if I think that the interrupt shouldn’t be a rune when it competes so heavily with damage in PvE (same with paladin). A worse Skull Bash baseline and the rune instead improves it somehow (adding a stun, slow, damage, locking out ALL casting, increased duration, etc)?
I think this would be a good and interesting change! It would allow you to choose between going for a glass cannon build that stalks the outskirts of combat to assassinate a high-priority target or for a rough and tumble fighter in the thick of it (maybe opens in cat, blows their energy and then switches to bear) that allows the group to survive longer. You can still choose between King of the Jungle or Survival Instinct on the feet slot for more damage or survivability.
Runes
- Chest - Wild Strikes
Gain the Wild Strikes effect.
Increases all damage done by 30% while in Cat Form.
- Chest - Survival of the Fittest
Reduces damage taken by 10% and chance of getting crit by physical attacks by 6%. An additional 10% damage reduction while in Bear/Dire Bear form.
All party members take 5% less damage.
- Leg - Rip and Tear (replacement for Savage Roar)
New finisher and should be treated as a rune replacement for Ferocious Bite.
This ability benefits from and triggers all effects associated with Ferocious Bite.
Different variations, just throwing them out there good or bad:
- You tear into the open wounds of your target instantly dealing X Bleed damage per CP. Each Bleed effect you’ve got on your target increases the damage by 10%.
Note: simple and clean but a bit dull and uninspired. Rake, Rip and even Pounce would increase the damage. Yes it deals BLEED damage and thus ignores armor and is improved by Mangle. Probably a bit overboard and makes Mangle mandatory. But it would also be unique (I think) and give this and the Mangle runes some synergy.
- Deals X Bleed damage per CP. Each CP deals additional damage equal to 20% of one tick of damage from all your bleeds on the target.
Note: so at 5 CP you would do additional damage equal to a full tick of Rake and Rip. A more complex version of 1 and I think worse and confusing. But hey, writing down everything that comes to mind.
- Deals X Bleed damage per CP. Has a 20% chance per CP spent of increasing the duration of your bleeds on the target by 2 ticks.
Note: without needing to spend CPs on Savage Roar you should be able to have Rip and Rake up on your target when you use this new finisher to get the two extra ticks. This would also increase the value and damage/per energy spent of Rip and Rake. A major downside of this is complexity for complexities sake…
- Deals X Bleed damage per CP and spreads your Rake bleed to all nearby enemies at its full duration.
Note: If this would spread Rake at full duration even at 1 CP it could be kinda sweet and somewhat unique. Rake does kinda mediocre damage so no insane AoE. Could add in a splash damage that increases with CPs spent but it should NOT become burst AoE. Say each CP spent deals 30% of the up-front damage of a Rake. It is a sustained AoE ability, not for burst. Keep in mind that the additional targets won’t have Mangles +30% bleed damage unless the feral actively spreads that which costs energy and CPs built are lost when switching targets.
- Deals X Bleed damage per CP and spreads your Rake and Rip bleeds to up to two nearby enemies.
Note: a potentially more powerful version of number 4 but requires more set up. Sustained cleave rather than burst or AoE. Keep in mind that the additional targets won’t have Mangles +30% bleed damage unless the feral actively spreads that which costs energy and CPs built are lost when switching targets.
Set up with great rewards!
My favourites are probalby 1 and 5.
Finishing thoughts:
It would be really nice if more druid runes had versions for various forms in them. Like Sunfire which has a caster version and a Feral version. Hybrids are in a tough spot of getting only a single rune for each role so there are no choices while classes with fewer roles have more variations. Even if their runes are poorly balanced and one is the clear winner they still have the potential. An example would be the Wild Growth which could have a Feral version. You’d have to give up Mangle (and with that a lot of damage) but gain survivability and the “support” function. How powerful it would be, cost, scaling, etc can be discussed. Just an example. Or Lacerate could get a cat version with either an active ability or just something as simple as it increases all your bleed damage in cat form by X%. It might not be able to compete against Mangles damage and group support in any way but it would be cool to not be 100% locked into a specific set of runes.
Heck, Living Seed could get an effect where your melee crits sprout Living Seeds on friendly targets for X healing. No one will probably ever take it over Wild Strikes but hey, it’s there and could be used in some fun and unique playstyle with the Feral Wild Growth. A feral support healer? haha
And as I said, this goes for all classes that have earmarked runes for a specific spec like this.
Combo Points!
CPs should not be removed when switching targets. This is just horrible design. At the very least they should stay on your target until you use a CP builder on another target. So you can switch target and at least do auto-attacks and then switch back. Or let us build CPs on multiple targets. This goes for rogues as well…
Other various ideas:
New ability or rune - Lick Your Wounds
15-20s cd.
You immediately enter prowl and start licking your wounds, regaining 25% of your health over 6 seconds or until you exit prowl. While you’re licking your wounds, damage over time effects won’t take you out of prowl but they still deal damage. For 30 seconds you deal 25% less damage, stacking up to 3 times.
Note: a more pvp oriented ability. You trade future damage for 1-3 “free” ticks of your bleeds and some health (roughly 500 with decent gear). This can be used multiple times to reset combat but with a harsher and harsher penalty.
Fits in a theme of a predator letting their prey bleed out while they patiently wait. A predator that weaves in and out. Feral druids got Maim in later expansions (stun finisher) but to mix it up I figured a more interesting path to take would be this bleed them out approach.
The heal might sound strong but keep in mind that there are a lot of stuff that breaks stealth besides DoT damage.
Rune - Smell of Blood
Each time you deal Bleed damage, you gain 3 Energy or 3 Rage.
Note: With Rake and Rip up this would generate ~24 energy over 10 seconds. A passive way of further increasing the value of our Bleeds (including Lacerate) without upping the damage. Heck a bear could open from Cat form with Pounce and a quick Rake and then go into bear for some extra rage while those DoTs tick. They could even weave in a quick powershift+Rake in the middle of a fight if they wish.
Skill Book - Track Humanoid
Your track humanoid ability now works in Bear form and is no longer canceled when you exit Cat/Bear form but is rather suppressed until you reenter Cat/Bear.
Note: just a QoL thing. It is annoying to reapply it every time you exit/enter Cat form.
Starsurge rebalancing
Up the CD to 8 seconds but increase the damage by 30-40%. Give it back some of its umph while not making it overbearing in PvP.