DOA5LR was already technically/graphically great and complete. It is hard to imagine how DOA6 could bring a NEW game which is not a refreshed copycat of DOA5LR. Here is my dream =)
1) INTERACTIVE LOBBY
From my point of view, it could be the most exciting feature.
Basically, you have a little MMORPG-like map where you can move around with an avatar (let's say chibi) in order to choose your game mode or interact with other connected players/friends (profil, ranking, predefined messages, emotes). You can also create a custom private zone (rings). It is something we already see in some fighting game (Dragon Ball Fighterz, Blazblue Cross tag Battle,...).
This is much more human-friendly than just waiting and accepting a fighting request in a empty black screen, or being listed in an ugly lobby array.
I think it's interesting for a online versus game to have an in-game representation of the community (who is playing, how many of them, in which mode, etc) simply more funny. To gather people in a visual in-game way.
It also opens to DLCs business too, other than only costumes (emotes, avatars,...)
People always want more and more content (stages, characters) but sometimes It is worth it to work on this kind of new system too. Also if I want to play a game with a deeper story, I don't play figthing games.
That's why I want this interactive lobby as a priority, IMO.
2) THE OTHERS
A main game for the competitives, by adding:
- Catchy music (menu and character select)
- A real PC port
- Efficient ragequit/cheaters management
- Full costume customisation menu (but not the bodies)
(- Lesser dumb Hitomi)
A side game for the fanservice with:
- Basically all the controversal-too-sexy stuff that should not appear in the main game
- Damn I want a serious multiplayable volley ball and mini games with all the cast
Both games could unlock content for the other (special lobby avatars, win poses, even characters, accessories etc).