According to CR, Canon EOS 7D Mark III will have slight crop when shooting 4K video. The EOS 7D Mark III is rumored to be announced in sometime 2018.
Below is the wishlist of Canon EOS 7D Mark III:
1. Better AF tracking.
2. Improved video.
3. Improved base ISO raw dynamic range.
5. AF Auto Fine Tuning
6. Built-in WiFi.