No, it was already confirmed a while back that the gameplay will be heavily influenced by KH3D. Notice Sora jumping off the buildings and heartless? That was flowmotion mechanics, introduced in KH3D.
In terms of Keyblade combat, It will likely play like KH3D and BBS (both games have the same combat style); that is where the series has evolved to. You don't have to worry about them going back to KHII's style of gameplay.
Well, plans do change after all and the only screens we have is with the old battle system. Still, there seriously has to be something wrong with them if they go back to KH2 combat rather than commands (make them more BBS and less 3D though).
The HUD is very likely just copy pasted on top of the actual video simulating gameplay like early 3D footage was, but still, I'd rather not have to consider the possibility.
What about the menu stuff from the first two games? That drove me up the wall. Is that gone?
BBS, Re:Coded, and 3D don't, but this trailer does for some reason.