I think it's probably unrealistic to expect new powers and stuff like that, as many resources - programming, art, animation, etc - as they require.
And a couple of the suggestions I know aren't possible - the Cryptic and Paragon teams apparently tried for years to get shapeshifting and size alteration working and it was just a no go in the CoX engine, and they said Speed Melee wasn't really viable because they made speed a movement power.
As a professional computer programmer for a living, I can say that this is bumpkiss. Virtually ANYTHING is possible in code, given enough time and resources. What prevents things from happening in the virtual realm isn't the POSSIBILITY of it, it's the lack of time, resources, and interest. Companies in general do what gives them the most bang for the buck, and I would expect that the lack of shapeshifting today is the result of the company and its employees looking into the work it would take, and the number of players asking for it, and answering "the juice isn't worth the squeeze".