Will they announce all characters?

[Weavel]

Or keep some secret? Did they do that with brawl? I don't remember.

P.S. I tried to find a forum with this kind of question but I couldn't so I made this one.

 

[Terrazi Terrajin]

We will very likely see all characters before release, as with brawl and the previous titles.(unsure of melee)

Whether they will be shown on these final 2 days of E3 though is another matter entirely, there's no more smash on the forecast, unless treehouse doesn't actually list their titles.