I played the demo a bit last night. I'll only list the issues I had with it.
1. Lack of punch buttons. That's what I used in Rd3 and worked well for me. It'll take me some time to get used to the stick. It's a poor decision, I think. The buttons were very precise but the stick seems to very sensitive to rounded movements.
2. Crosses just seem to be jabs. They have similar speed and you can rapid fire them all day. For a lot of fighters, the right cross is their money punch. Not sure how that would work here. You'd bascially be nullifying a lot of the roster if you properly spec'd out the fighters.
3. Footwook is missing just as before. Lots of fighters got to the top by having amazing footwork. Footwork is essential to setting up punches and combinations. However, the focus of Fight Night seems to be all about what goes on above the torso.
4. Combinations. They need to be a bit more realistic. A jab, cross, left hook, cross combo should be faster than, left hook, right cross, left hook to the body, right upper cut to the head. They're the same speed in the game.
I'm still getting the game but there are some clearly issues that need to be addressed going forward.