Long time lurker on this thread, reporting for duty. Finally got tired of stalking, and I thought I'd never see the day.
I hope very desperately that Shulk gets in SSB4, but I am not expecting him nearly as much as a lot of you. After reading what everybody's had to say, I give him a 60% chance, maybe, but I really don't know much about how this all works, and I don't want to get my hopes up too much just to have them crushed. (Xenoblade is my favorite game, after all.)
What I want most out of a stage is a traveling stage around the Bionis, like Delfino Plaza (as has already been discussed, I guess). Alternating between day and night, of course. I just can't make up my mind between Gaur Plains, Satorl Marsh, Prison Island (on the outside looking over Eryth Sea, of course), and a sweet shot of the Bionis and the Mechonis just looking generally awesome as they do, so a traveling stage works best. And as much as I despise stage hazards (I refuse to play on any Metroid stages or Spear Pillar for this very reason), Metal Face as a boss on Prison Island would be awesome.
I would probably die of happiness if Shulk got a CG trailer, at E3 or otherwise. I just don't think I could stand to wait until after the game has been released to see if he's in it, especially since I would have to wait for other people to find him (alas, I will be getting the Wii U version of the game). Imagine, characters (Link and Mario and Kirby or something I don't care they aren't the coolest part of this) running from something, and being surrounded by a hazy black horde. They try to fight it, to no avail. Their attacks do nothing. They get surrounded by even more, the circle closing tighter, imminent doom approaches, and BAM! CUE MECHANICAL RHYTHM, SHULK DROPS IN, THE BLACK THINGS ARE REVEALED AS MECHON, HE STARTS KICKING INSANE AMOUNTS OF BUTT, HE HAS VISIONS OF THEIR ATTACKS AND IS DODGING EVERYTHING, NOTHING CAN HIT HIM, IT'S LIKE LEVEL 80 NEW GAME+ PLAYERS AGAINST A FEW LEVEL 2 COLONY SKEETERS, ABSOLUTE DESTRUCTION, WOW THIS IS SO COOL WAIT WHERE DID SKITTLE GO OH LOOK HER HEART STOPPED
...I might be a bit too excited about the prospect of this. Heheh. I'm really surprised most of you mention You Will Know Our Names for Shulk's trailer, and not Mechanical Rhythm, which begins with a bang and maintains that brain-exploding coolness the whole way through. ('Course, I'm not the biggest fan of YWKON. Maybe because its presence came with too many heart attacks during the game.)