Being single player doesn't suddenly make a lack of balance perfectly fine. It's not unreasonable to say that people would enjoy some level of balanced challenge when purchasing a game. Difficulty levels (which should get introduced here) designate which amount you want.
Including a balance-destroying set of feats that is simply better in all ways due to AI mechanics is not just okay in the same way it's not just okay (if you recall) to keep Winterbreath the way it was.
If you really want to break the balance, modding will allow you to do that. Balance should be king in the vanilla game though if the difficulty levels are going to have any real meaning.
In other words, difficulty should be derived from a choice of difficulty, not from having to choose the far-best or sub-optimal routes specifically to get certain amounts of challenge. The feats should be for flavor of fun in the challenge. Not a re-write of the challenge rating.
