Does the APG change any of the best builds for treeant guides, specifically the ranger? I'm building a ranger for a game that starts next week.
Yes and no.
Yes in the sense that their are new potential builds/combos that you can play with.
No in the sense that the guides are still good. They just do not include any of the new stuff.
The guides that Treantmonk has are that: guides. They are his play style and he gives his observations on them. Some of his views might change with the new stuff, but you will be fine following his guides when building your character. You just might not delve into the new stuff as much. :P
I was just thinking today that he has a lot of work to do.
I think his guides are useful, in that he ranks the usefulness of class abilities. If something is rated Blue, and you are thinking of giving it up for an alternate ability... think twice and then think again. You don't always have to maximize your character. If you really want to build a concept, or you really like the alternate feature even though it is not as powerful than taking it is not "wrong". But his guide should give you an idea of what you are giving up.
Btw of all his guides, the ranger is the one I disagree with most. I suppose because his "Aragorn" build is not a maxxed out build. I and another player are playing rangers in a large party. I am playing a TWF ranger with sword and board feats. I'm regularly frustrating the heck out of the Treantmonk build. In a sense, it's not a fair comparison. We are regularly fighting creatures on my FE list and I am a specialist. So we are right in my wheelhouse. The other character is a very capable archer and a very capable melee fighter. Not stellar, but capable. That's pretty amazing to pull off, 'cause usually a build is great at one and horrible at the other. So consider using it, but realize you will never be AWESOME at either... but you will be capable at both.