It clearly has hands, 29 strength which is awesome as well as huge size, 21 con, but only 8 dex. Still a wizard poly morphing into that thing wielding a spiked chain could be pretty sweet. If only it could be enlarged to colossal

. I'd also gain animate trees according to polymorph text. I'm liking the wizard build more now. What's your reccomendation for wizy progression if I am going for tripping treant... I feel like he should have a vine colored chain.
You would not gain Animate Trees, you only get Ex special attacks, not Su or Sp. The only Wizard progression you can do if you want to start with Polymorph is Wizard 7. From there, it's up to you. Wiz 8 advances BAB, and you need Fighter, Barb, or Ranger 1 (or Paladin, but why would you?

) to enter Eldritch Knight, which will cost you a 2nd CL, but ultimately will provide full BAB and casting progresion with a d6 HD, which makes it worth it for a melee-focused wizard. I said do melee class 1 / EK 1 immediately so you could get the other feats you want right away and move on with the build. Feel free to go to Wizard 8 first if you want. I would not go past Wizard 8.
So with school specialization and 18 int I'd have 3 uses of polymorph at level 7. I would then go fighter 1 and into eldritch knight. this seems somwhat limiting and I wouldn't increase in what HD monster I can turn into until level 10.
It would set you back on finding better monsters for a bit, yes. But you use your own BAB, hit points, etc... so it's not like it's making you much worse off. When you're looking for monsters that can use weapons, even the 15 HD options aren't that much of an improvement from what you can get at level 7. Polymorph 3/day is limiting, Wiz 8 would make it 4/day. But you're thinking of Rage builds that would only be 1/day for shorter duration, so it's not that bad.
On a side note, just noticed Wyvern is 7 HD and absolutely amazing for any situation where you can't trip anyway but still want to tear things up.
earlier you said I could cast polymorph as a 6th level wiz.
I never said that.
Wizard polymorphed treant (dwarf):
Average HP: 54
Strength: 29
BAB: 3
Trip bonus: 21
Ranged: 30
Feats: undetermined wizard feat, combat expertise, improved trip, chain prof. DUE TO DEX OF 8 FROM TREANT COMBAT REFLEXES IS USELESS
Damage: 3d6+13 (assuming no up close use of claws/bite)
Speed: 30
Hit bonus: 12
Size: huge
AC: 8
Other things: trample, can cast 4th level spells. CAN ONLY POLYMORPH 3 TIME PER DAY, very low AC.
So thoughts everyone? These appear to be the three builds.
HP would be 28 from con +4 1st HD maxed + 2.5*6 = 47 on average, not 54.
Dex bonus magic items would still add to the creature's base dex if it's below 13 for Combat Reflexes, and no one is forcing you to use a Treant. If you're facing lots of weak enemies and want to use the feat, take a large sized form and lose a little str and reach. You can be a little flexible to the situation with this build.
I think you forgot to subtract 2 from the attack bonus for Huge size, unless weapon enhancement or something is making up for it.
You forgot to add the creature's natural armor bonus to your AC. You WILL also have Mage Armor up, so that's +13 natural for a treant and +4 armor. Your AC is 25, but your touch AC is craptastic, as I alluded to earlier.
The stat blocks also don't do justice to the buffing and versatility this option offers. With scroll making you can provide the party with cheap buff effects easily, and you can give yourself and/or them Haste, Fly, etc... when needed. A spell like Displacement or Blur for a miss chance helps with your cruddy touch AC, and so forth.