Emok:
Why would I buff our enemies? You big folk think size is an advantage?! :P
It is for maneuvers, and we have a monk, so it seemed like a good pick to me - but I'll admit it really depends on what sort of approach to combat we decide to take.
Taking it for Baleful Polimorph does seems like you'll need to wait a long while before you can use your bonus, but I suppose I can admire the positive thinking! ^_^
In case you do want to look for options to use your bonus before you reach level 10, here's a handful of other options for offensive transmutations; they might not all be great, but at least it gives you a chance to decide what sort of focus you'd prefer to have, right?
Spell Level 1 - Snapdragon Fireworks, Touch of Gracelessness
Spell Level 2 - Diminish Resistance, Pyrotechnics, Steal Breath
Spell Level 3 - Hostile Levitation, Slow
Spell Level 4 - Calcific Touch, Firefall, Obsidian Flow, Rigor Mortis
As I said, they're not all good (certainly nothing other than Slow and Pyrotechnics is anywhere near as powerful-for-its-level as Baleful Polimorph), but hopefully they might give you ideas? Although I still think that Reduce Person isn't bad, in the right circumstances. :)