Let's get into some speculation, shall we? (Hopefully some of my ideas weren't already mentioned... I had to skim most of todays posts while at work.)
Now.. do we think this is a screenshot of the actual FINISHED menu from the game (before the player has unlocked anything), or is this a dev-screen specifically altered for the website?
What I am getting at specifically is how the character icons are grouped together in the middle, and obviously only characters that have been revealed already are shown. Does this mean that we're looking at the entire starting roster here (and should expect no more new character updates before the game's release), or does it mean that Sakurai just had the last few (unrevealed) characters of the starting roster removed from the menu just for this update?
(Also, if it means the former... would it mean Sheik really is gone? Notice how ZSS and the PT's pokemon are given their own icons...)
Edit: I still think we are due for 2-3 more starters (such as Captain Falcon), btw, so I am sure this screenshot was altered for the site. I'd be surprised at any other outcome... it's interesting to speculate though.
Another thing I noticed... the Miis that are selectable as icons have a different background color that separates them from the playable character icons. Does this mean we won't see a playable "Mii Fighter"? Not necessarily, but it seems to lower the chances of one to me.
OH one last thing about this screen.. See the "PROFILE" heading at the bottom? Do you think this menu has further customization options beyond your avatar and your four taunts? Or maybe some stats on the right side?
Player 3 is selecting the stage... does this mean he is the host and the host chooses the mode/stage, or might it be a system like Mario Kart DS where all players get to vote for the stage? Hmm!
OK most of my speculation is rather obvious and isn't actually all that insightful... but I felt like pointing out some tiny details I noticed anyway.