I like them and would like to see a base version of them even in Core, something along the lines of gaining advantage on you next roll as a benefit.
There could be many options on top of that.
In a module, to represent that extra "push" of adrenalin I'd like to have them grant an extra action but you only gain one the first time you become bloodied in a battle.
Or just gain one every time you to help represent revitalization (though tough to balance and in 4E this would have broken the game for melee strikers if the limit on one per encounter were lifted. In 5E it would likely have to be limited to gaining an advantage roll)
Etc.
There could be many options on top of that.
In a module, to represent that extra "push" of adrenalin I'd like to have them grant an extra action but you only gain one the first time you become bloodied in a battle.
Or just gain one every time you to help represent revitalization (though tough to balance and in 4E this would have broken the game for melee strikers if the limit on one per encounter were lifted. In 5E it would likely have to be limited to gaining an advantage roll)
Etc.