I was about to come in post what — did.
I think the number one feature is native exporting. I know it's a huge task, but I know I would be willing to buy and upgraded license (above business) that support multiple native exporters. I'm not even sure if it's possible with C2, but game maker is doing it, unity does it, this new one called Spark Tools is coming soon
I just think the dependency on third party wrappers needs to come to an end. I would be happy if we could natively export to say Xcode/Objective-C and then let us worry about getting things like ads, game center, etc. working in Xcode. For those of us that want this advanced featured.
Now I understand that this feature is a bit more advance and is probably a pretty small percentage of your user base. I get that, I just wanted to voice my opinion <img src="{SMILIES_PATH}/icon_e_smile.gif" alt=":)" title="Smile">.