For all the claims of Clerics & Druids being overpowered, I still rarely see people play them, especially Clerics. The class just does not seem to appeal to a certain type of personality, and apparently my friends have it.
I like Bo9S, I think it does increase fun creep more than power creep, but again it is book of classes that require alot of management, which is not going to appeal to some people.
Anything that takes away, move, Attack, Full Attack, move. Some D&D combats feel more like watching an old comedic boxing match, where both participants either run away, until they reach a point were either they are cornered, or hit the spot of their choosing and full attack.
Activities Like Sundering, Bull Rushes, Tripping etc are more flavorful when handled by maneuvers and instead of by precious feats.
I also think it can reduce in some ways the damage output of melee characters. First off, the high level maneuvers have saving throws, which is something that does not apply to the Hasted, Divine Might, Power Attacking Paladin with a Holy Keen Falchion and Bless Weapon.... there was not a power deficiency for melee-ist at high level, melee-ist are more powerful than casters at that level in terms of DPS, but a coolness gap.
The second main balancing factor is alot of those strikes are standard or full round actions, which will take itterative attacks out of the equation.