Has to be a new sensor, preferably APS-H which would allow 24MP with larger pixel size + greater density than the current 7D has with just 18MP. Same or improved AF would be nice, as would dual memory card slots, and of course dual-DIGIC5+ chips (guaranteeing at least 10 shots per second), with a noticeable improvement in DR from 11.7 to 12.5 EV (DR is directly a function of Pixel Size so the 4.3 micron pixels in the 7D1 need to be bigger, so possibly a 24MP APS-H sensor that was 30mm x 20mm would give us a 5 micron pixel size whilst retaining a 1.2x crop). A new APS-H sensor (which was originally developed in mid-1990s to match the arrival of HD TV's) would go some way to improving 'shot' noise, then new processing power of the DIGIC5+ processors would obviously contribute by reducing 'read' noise, as well as boosting ISO performance by 1-2 stops. It is not simply that bigger sensors & more MP = higher noise, the Nikon D800 disproves this theory. More pixels on a bigger sensor with better quantum efficiency + better algorithms/processing power = improved IQ
