Upload & Sell: Off
If Canon were to do nothing except upgrade the sensor in the 7D for the 7D II- that would be enough.
It'd just be silly for them to not support the other features that they've introduced- in particular, the 7D II should have GPS over WiFi, if it doesn't have both.
Other than that? Not much, really. We don't need more resolution in a crop body; if anything, 18MP-20MP is fine, especially given how well the 700D is performing resolution wise with a current spin of the 18MP sensor and accompanying anti-aliasing filter, processor, and firmware.
Other nice-to-haves would be dual card...Show more →
You forgot the big one.... AF!
Don't forget the camera also needs to sell for another four years not just four months too.
Anyway things that certainly could be improved:
As you did mention all the sensor stuff, the low ISO DR is pretty far out of date. While the high ISO on it is pretty good for APS-C, if they used 1DX/6D tech in it it could pick up an admittedly minor maybe a trace more than 1/3 stop SNR and a more noticeable 1+ stops of DR at high ISO. Most copies tend to suffer from varying degrees of vertical gain banding and it has a heavily green split CFA so debayer makes it a bit softer per pixel than it otherwise would need be.
The AF while it is faster and has more points than the xxD line and can be a bit more precise is still very clearly not to to 5 or 1 series level precision and the tracking, other than seemingly for surfing, is a far cry from 5 or 1 series IMO, especially for stuff like soccer and football where it seems to be a lot closer to the old xxD levels than 5 or 1 series levels. And yet this is supposed to be a body focusing on AF and action so it really could use their top level AF and not a souped up but clearly based on low tier AF.
The dual-phase AF thing would be neat.
Add the little UI tweaks of the 5D3 such as instant 100% review, auto-updating C1-C3, etc.
The movie mode is pretty poor by current standards, aliasing, moire, very soft, low DR, poor SNR, poor usability features. Now ML does get around some of the usability and ML RAW might get around the softness and some of the poor DR and a tiny bit if the poor SNR, but it won't fix the aliasing and moire. So for those wanting to use a 7 series for movies it could be improved a lot.
Going 8 to 10-12fps could help a little bit in that you might go from a near two guaranteed key frames per action sequence to neat two guaranteed ideal key frames per action sequence (and at times you might get a third at 12fps) and since AF does miss at times and what not it gives more chance that at least one key frame is in perfect focus (you hope).