I don't know what CC is.
edit: OH, I get it
I like Gmail because of the threaded view. It's old hat nowadays but the fact remains that the threaded view is quite simply leagues better than old-school email inbox views.
I'm not saying it can't be improved, but it's a very good ux. I even like the new compose, once I got used to it.
As for CC... why do you need it? Just add the address to the "To:" field. The result is the same. The only time you need to put it in a different field is for BCCs, and quite frankly I imagine most don't use that feature.