Once you owned 5D III, your 7D will most likely sitting in the bag & collecting dust - or end up on CL.Mine doesn't. It has been demoted to "second body" position though, but I use two bodies often enough, and the 7D complements the 5D3 quite well. In particular I like it that their ergonomics are pretty similar - much more so than between 7D and 60D I used before. And sometimes 7D *is* better, in particular it has longer burst length, and in good light the extra reach is sometimes actually useful (well, just about enough to offset the generally better IQ from 5D3), so that a shorter lens (24-70, say) in the 5D3 and a long one (100-400) in the 7D make a good combination.
I would still be interested in 7D mk2 if it had sufficiently better IQ, especially with high(ish) ISOs, that it would produce visibly better pictures than the 5D3 in focal-length-limited situations. Better AF, higher fps and longer bursts (with raw) would also be appreciated. Everything else, like WiFi and GPS, would be icing on the cake - nice but not important.