About the same
Physically, the 80D is relatively unchanged from the 70D, which means Canon missed the opportunity to fix some of the more annoying aspects of the design.
Mode dial additions
One nice change is the addition of another custom-setting slot on the mode dial. Canon also added a special-effects mode.
Unchanged controls
There are no changes here, but that's OK because the existing layout and works pretty well.
Back buttons
The one small change Canon made here was to fix the Q and review buttons so that they're not so flat and hard to feel. However, I dislike the navigation rocker (circumscribing the Set button), which is very hard to press accurately, and that remains.
NFC
Canon added NFC to supplement its Wi-Fi connectivity.
Connectors
Canon did the most here. The 80D gets a headphone jack, so Canon moved the remote connector down below.
Swap
Canon reversed the positions of the HDMI and USB connectors.
New mic
With the 80D, Canon also announced a new directional mic.