So far, the only issues I know of when developing for unsupported systems is the lack of Unity's version for those platforms. E.g. WiiU is still on Unity 4.3, so you can't use the ORK versions since 2.2.0 (which require Unity 4.6 due to the new UI).
Don't know what Unity currently has running on PSVita - if you need an earlier version of ORK you can contact me :)