Having both the 7D2 and the 80D (as well as the 7D) I can say there are some small differences between the sensors. The 80D has a bit better DR at base ISO, there is little to no difference by ISO 400, and above ISO 640 the 7D2 is better, especially once you pass ISO 1250. The 80D has a bit more resolutioat 24MP vs 20MP.
The biggest difference is the 7D2's AF is much better than the 80D for small birds (so is the 7D's). I use the 80D mainly for landscapes at base ISO, multi-shot HDR merges, and just general snap shooting. I use the 7D2 for small birds, and also for general shooting. Having said all of that, the two bodies are nearly interchangeable.