The limitations to RAW are that you can only take creature features, some minor abilities, speed, strength and toughness powers. There also is something to consider in the fact that Modular abilities power is called "Function Follows Form" and it is a shapeshifting power, this implies that you have to have a visual reason why you get that power, in that your physical form actually changes. Maybe I'm wrong but it would seem to me that the guy who buys inhuman recovery would look normal but the guy who has modular points put towards inhuman recovery at all times, would look as though he was not human, maybe close but somehow, off.
Thats my read on it at least.