Warrior is really strong on some fights, and at worst strong on others.
Take a look at this:
https://www.warcraftlogs.com/zone/statistics/35#aggregate=amount&dataset=90
It is not as much doom and gloom as one would think.
https://www.warcraftlogs.com/zone/statistics/35#aggregate=amount&dataset=90&metric=bossdps
So I think we can agree we are more than fine in a raiding enviroment.
For M+, sure we are not the best, don’t understand how making warrior harder to play would make it better in that content. Guess you want warrior to juggle stacks and buffs, to react to 3 different things while minmaxing spending to a level only AI driven macro work can do.
Now, if you want to solve warrior issue in M+, you need to address the core failing we got. That being: Others bring more damage and utility. So, a simple fix would be to just bump up warriors damage to the point of being viable.
If retribution can compete with warrior on the meters (or go beat a warrior, something that they do), then warrior would not be brought even if it had CR or Heroism. As Ret would be the better option. Now, if warrior can selfsustain and outDPS a Ret consistently, then you can start thinking about bringing in a warrior. Now, if DH brings more damage than warrior and Ret, you simply bring a DH instead - to the point a DH dies, where a ret/warr wouldn’t.
So, they could go another route. Simply just give us more Spell Reflectable effects that consistently hit the warrior on a 15-20sec intervall in the dungeons we struggle to be effective in. This to make others have it harder, and us easier. Bringing us makes it easier for everyone, as such we would be desirable. Not to mention, we would directly scale with the key level and not be overpowered low-end, but gradually more powerful high end.
AoE combatress and Heroism in itself would not solve anything. As it is not the core issue.
Personally? Just buff OF by 100% baseline, give the DoT an uncapped effect and a 250% increase on the damage modifier. Finally, make OF do fire damage to make our damage consistent and fun to watch blowing up on the screen.