De-ranking spells was limited in Value in TBC already and slowly faded away. Since that pretty much only arcane mage uses mana in their rotation. And all healers.
And if there is no down-ranking you can’t really implement a mana based system… like you can have mana return if you do your rotation correctly but then the margins would have to be extreme for it to work, punishing if you make a mistake and for every new player (DPS nowadays is extremely high ceiling).
It’s for specific classes that have their rotation set around this. What’s the point in having all caster DPS designed in the same way as arcane mage? Stack icon X to deal more damage but using way to much mana, then cast Y to drop the stack to start dealing much less damage, gaining mana. And if needed use a long cooldown that increases mana regen - maybe we should delete all other specs if all will be the same?
There are combo points, energy based melee classes, holy power builders/spenders etc. - you can re-do mana into something like this but what’s the point then? Even more classes having same rotation mechanics/resources?
Nothing fun in enforcing old systems just because many years ago they were used for completely different class and content design.
In vanilla people were so bad that even mana management was way above their skill level. In Classic people optimize consumables, stats, gear. Healers know which ranks to cast, casters chug mana pots, dark runes on cooldown and the DPS is so high that fights last way way less than originally making mana not really an issue.
And mana died because at some point people got to the same level as now in Classic - making it “not a real mechanic”. It’s very hard to balance casters around “for 25%-35% of the fight they are oom and do nothing” while also making someone play them instead of non-mana classes that would perform way more reliably.
As a MW healer I had to learn mana management hard, really hard, but can’t really see it for a DPS class aside those that are directly build around it like arcane.
I played frost mage in Classic where top DPS was pressing 1 button with mana gem, evocation, mana pot/GFPP in between and rag was dead. I also leveled and geared a frost mage during BfA and to get a green parse I had to:
- learn the rotation
- improve the rotation based on wowanalyzer suggestions
- pick correct secondary stats, enchants, talents as suggested by the theorycrafted and simmed guides
To get blue or higher parse I would have to get BiS azerite traits. Then to get purple I would have to play a lot and get every encounter timed in memory to use cooldowns, short cooldowns, trinkets and procs optimally. Current game is very complex for a DPS player that wants to perform close to what’s possible. This isn’t vanilla and RPG style mana for casters.