I think there's a lot we can learn from this, honestly. Particularly when you take into account
RYCE'S 3DS ROSTER as a likely final roster there, then try and re-arrange things to fit with the Wii U screen...
The biggest thing for me is that Greninja is in front of Pikachu on the Wii U screen. That says to me that Pikachu will be the first slot on Row #4 and Greninja will be the last slow on Row #3. Which is strange, because so many of the bottom characters are "one-offs" that could easily be rearranged. Why is Greninja separated from the rest of the pack?
Here's a rough mock-up of how the Wii U screen SHOULD look... wish I had the editing chops to actually make it look like the Wii U screen, though, ha.
Everything lines up as it does in the demo screen. Four biggest Smash characters on the far left. The "sibling series of Metroid and Kid Icarus take up the top right, with their retro pals. Ganondorf remains a clone and remains next to Captain Falcon. Fire Emblem and Mother remain side-by-side. You could easily drop a Star Fox character to squeeze in Lucas, too. Game & Watch sticks with the 3rd Parties, and also with Wii Fit Trainer, his modern "named after hardware" pal.
The only area I'm iffy on is Captain Falcon through Ice Climbers and ROB. They seem distributed sort of haphazardly... and the bottom row in general still doesn't make sense to me. Why not move Olimar up some and bring Greninja down? Why is he before Pikachu!? I want answers Sakurai!!