Me, I want the following:
1. Them to add back in the cut dungeons and content that was blatantly removed and replaced by boring crap like the Triforce Quest. Because come on, everyone wants a third dungeon near Greatfish Isle where you get the last pearl, right? And a new dungeon to replace the Triforce chard/chart hunting?
2. A boss rush, because we so need a way to refight Gohan, the Helmaroc King, Phantom Ganon, Puppet Ganon and a couple of other such bosses that we can't refight in Ganon's Tower.
3. A Master Quest mode. I loved this in Ocarina of Time 3D, and I'd love to see an equivalent for The Wind Waker too. People complain the dungeons are too boring and easy, now imagine them with all new puzzles, ten times the difficult monsters in each and some real major redesigning.
So what do you want to see in this game when it's remade on Wii U?