This is true, you've also got some people almost vehemently expecting that which wont happen in a million years, Smash brings out the loonies that's for sure.
I agree, it's silly when people think their favorite character in some obscure game is going to get in even though he realistically has no chance.
On a completely unrelated note, I can't wait to play as Jill!
Eh...this isn't a concern born out of paranoia. This is based on what we're told are Sakurai's own plans for the game:
"What Sakurai hopes to do is have the 3DS version of Smash Bros. allow players to build up their character through battle and rewards, then take their custom character to the Wii U version to face off against everyone."
Source
See, I don't get how you're reading, "These are the only things we expect to do with Smash 3DS," from that.
I read it as, "These are some new features that we hope to implement that give an example of how the Wii U and 3DS versions can work together."
Releasing Smash without multiplayer would be like, I dunno, releasing Half-Life without single player, or if all you could do in the next Madden was kick field goals, or if you took the exploration and discovery out of Metroid and made it linear, mediocre character action game with cutscenes that are far too long and embarrassingly bad and portray Samus as whiny and subservient and useless and the worst character in anything ever, except maybe Adam.
...Ahem.
This is Sakurai. If there's one thing he's known for, it's jamming as much as possible into his games, and then adding some more on top of that. Smash 3DS is going to have single player, multiplayer, and there's a reasonable chance that he's going to invent some new number just so the game can support that many of players.
