The polymorph subschool spells all have dumb restrictions and were a huge step in the wrong direction, IMO. Swift action, selfish (self-only), short duration spells with big temp hp boosts. They basically exist solely to pwn in melee better than the warrior classes and have no other use at all. That's...horrible.
I much prefer the actual Polymorph spell. Has a moderate duration for utility uses, and you can buff other PC's with it. Alter Self, Polymorph Any Object, and Shapechange are broken. IMO, the polymorph spell is not. Some later monster manuals printed creatures with outrageous stats and/or attack routines (like the cave troll, war troll, and arrow demon), but most creatures aren't that unbalanced to turn into and the polymorph spell limits you to Ex attacks, not qualities, Su, etc... And none of the really strong/exotic creature types, like incorporeal/undead, outsiders, constructs, and so forth.