The lack of healing factor display I believe was largely for the same reason as Wade himself comments in the movie; small budget. The feel I got from it was twas a bit of an experimental film so they didn't splurge all that much funding on it, awesome though the result was >> with a bit of luck we'll get a similar case as with How to train your dragon; good base, even better sequel. I'd have said Thor cause the sequel was significantly better as well, but then I remembered the original was kinda shit, so eh.
Speaking of sequel though, to my knowledge the Cable thing is mainly just a half rumor, half consideration. Only thing they have planned for sure right now is not to do further X-men crossovers, at least not yet.