With Complete Mage, Bo9S, PHBII, and other 3.5 books from WoTC, there have been some comments about power creep. I was curious about how everyone felt. Answer away!
I dislike Tome of Battle as written. I'll happily nerf some spells, and boost some others. The frenzied berzerker drives me to distraction. There are some things that I think are too powerful, and they're not in my games. Easy enough.
I like the rate at which WotC is filling out the game lately. A lot of interesting things are now possible, and I haven't felt any particular disturbance in the force.
Hmmm, I do not know if it counts as 'power creep' or not, but I have found that the Reserve feats in Complete Mage definitely change the pace of the game. The party is much more likely to push on a bit further rather than wait for the wizard to prepare his spells the next day. The net result has been the party as a whole taking more damage, and the wizard, umm, reserving his spells until the rest of the party is getting low on resources as well.
I voted for "a bit." With more options, there's bound to be a little bit more optimization than there is with less. I don't think it's drastic, but I don't think it's non-existant. The caveat is that I haven't played with many of the "alternate system" books like Bo9S.
I think the power creep, all things considered, is nearly non-existent. There are a few options more advantageous than others for any given character concepts, but these discrepancies have been around since the core books released, I think. In the end, the players and DM make the balance happen around the table, not the books.