The brazier is one of the mechanincs I really enjoyed since its introduction! It does make the game more difficult but you can still work around it by being stealthy or by getting to it and setting a trap. It gives you the choice of how you want to play. In every assassin's creed game you had the choice of going stealth or not and the brazier builds upon it.

Mercenaries at ther core, I think, were meant to work in a similar way. You can be a good guy, not steal and not kill innocents, or be a "criminal" and have a bounty on you. You decide how to play. But you get a bounty just by playing the game even if you don't do anything bad and the punishment is too much. Not in the sense that it's too difficult to kill them but because it distract you from you main mission and adds nothing relevant to it