Eh, metamorphosis was the strongest power other than affinity field + shenanigans a psion could ever take.
Toning it down wasn't really an issue.
PF has a lot of houserules, but most of them don't do much. The fighter is still T5, maybe T4, the wizard is still T1, just with slightly less cheese... when I read over the rules, it didn't seem like it was worth the headaches of learning their tweaks and changes and new subsystems in order to play a game that was functionally identical to 3.5 but with more little fobbly bits and a bit less customizability.
Plus it looked like I wouldn't be able to run monsters straight out of the MM on the fly anymore, i'd have to convert first, which is just a pain in the ass.
EDIT: That said, there's a bunch of pathfinder society guys who run games and I know a few of the regular DMs are great DMs (why they're running canned modules for strangers I do not know), if PF has auth'd this psi stuff for pathsociety use, i've wanted to play a low level shaper for ever so long.