They showed off this neat little tech demo at E3 where you can zombify your face using the pad's built in camera.
I am hoping it becomes more than a tech demo and you can map your own face to a zombie that can then spawn in a friend's game. Somehow I doubt this because it would be such a great feature that Ubisoft would have already shown it off by now.
I am also hoping you can do motion controlled melee combat, the Wii U pad essentially has the tech of a Wii Motion Plus so it should be pretty much 1:1. While the idea is cool the Wii U pad is quite expensive so I think Ubisoft wouldn't have included it for fear people will break their pads.
I think I'm going to have a lot of fun with the Demons Souls style messaging system. If you're not familiar with the game its essentially a way to leave a message in the game world by leaving a glowing message on the floor. You can't see the message straight away you have to go up to the glowing thing and press X before you can read it. What's fun about it is you can use it to either help or troll other players, but you'll never actually know if you've helped or hindered someone because your messages randomly show up for others. You don't even need to be in someone's friend list, all the messages are a result of the community as a whole. I remember this guy who saw a message that said there is a dangerous enemy ahead and to attack immediately but turned out to be a non-hostile character important to the story. You can permanently kill story characters in Dark Souls by the way and you can't reload your game, they are dead until the next playthrough.
Of course in ZombiU you can't write anything, you just have a bunch of predefined symbols you can select from to convey your message. Its like some kind of UV spray paint on a wall that can only be seen with the scanner.
Ubisoft mentioned you would be able to hunt down your friends infected survivors (not controlled by your friend) though its also not just limited to your friends but also other random players. There will be stats as well to see if your infected survivor has killed someone in their game.
People who were at the Eurogamer Expo said the handling on the guns were kind of sluggish, I'd put this down to the skill levelling system. Where when you start out as a new character you're essentially a newbie with all weapons and you handle them poorly, and the more you use them the better you get. When you die, you lose all your skills and start anew. People also said the game was incredibly dark, too dark even when using the in-game flash light which sounds like the people there didn't setup the gamma correctly either in-game or on the televisions they were using.
People also said they were disappointed that the sniping sections were not 1:1 motion. I can imagine why it wouldn't be 1:1, because you would have to hold the Wii U pad with the same precision as a real sniper rifle. Some guy also tried turning around 90 degrees while zoomed in to acquire his next zombie target which isn't how a sniper rifle is supposed to work. Like in real life you point the gun in the general direction of your target, zoom in on the scope, shoot and repeat. Don't make this mistake when you start playing.
I'd also like to point out its not the first game with real-time inventory management. I remember Demons Souls, Dark Souls and Resident Evil 5 had it but of course its not the same when you can see everything on one screen.
As you can see I am a huge fan of this game because I've been digging up every little bit of information about it since it was announced.