I think it will have a dark souls - esque multiplayer. Not the invasion, but everything else.
EDIT: Also, I would like to know your opinions on the two following systems:
1) The rental system in ALBW: This opens up all the the world at once, but are hidden behind a paywall. Naturally, then, the more expensive it is, the harder the dungeon will be (at least that was the theory of it). Although I am personally not a fan of it, it does open up the world instantly.
2) The upgrade system of SS: It was frankly useless in SS but it was very fun as well. Combine items with rupees to make your items stronger. It was great! I don't know how I'd feel if it served a greater purpose though. Even if this stuff is optional, I'd hate to miss out on a piece of heart just because my item isn't strong enough just yet. I also wouldn't care for a more complex system though I think people will dig that.
The rental system isn't inherently horrible. They just didn't handle it properly. Theoretically, you could have dungeons with a lot of variety in complexity and items usage.
Theoretically ALBW could have had some of the best dungeons in the series. Because, they should have been able to have the dungeons use any number of items they wanted, because they knew that the player had access to all the items. The problem is I think they got scared. "Well, we know the players
can have every item, but we don't know that they
will have every item." I think they were scared that the player would reach a dungeon that required items they chose not to buy, and get frustrated or annoyed, even though the player could go back to the shop and buy the needed items. So as far as dungeon complexity, the rental system can still deliver that, even though it didn't in one game.
That said, the rental system really does hurt the good feelings of progression that you get from actually finding items, whether in the dungeons or overworld. If you know all the items, then you get an idea of how all the dungeons will work even before you get there. It just makes the whole thing more mundane. Like it's link's job, rather than an adventure. I'd rather see the non-linearity handled in another way.
The upgrade system is cool. It was fun getting a faster beetle, or one that could grab things. It was nice seeing different types of shields. Keep it, but expand on it. I actually think the upgrade system from ALBW was better than SS.
Seriously. We need to see old school pig Ganon back.