Fatmanonice
Banned via Warnings
I think this is a pretty solid theory. As you said, Megaman and Sonic are obviously unlockable and Luigi, Marth, Toon Link, and Lucario have a shot of being unlockable too based on past patterns, bringing the lowest number for the starting roster at the moment to 23. Now let's build up to the number you proposed. Ice Climbers, Wario, Metaknight, and one Mother boy have all but been confirmed for the starting roster. That brings our total to 27. Minus Squirtle and Ivysaur, now we add the only character in the Brawl starting roster that hasn't either been confirmed or strongly implied, Ike. We now have 28. That then leads at least 5 additions to reach the number you proposed. This could either be made up of newcomers or a combination of "promoted" veterans and newcomers. With at least three months left and how we got 9 characters in a four month span, I don't find it unreasonable that they could build up to 33-34 by July/August, especially with E3 coming up and at least one other general Direct being very likely before or after E3.Um, if Ice Climbers were separated they wouldn't really be all that unique and wouldn't add much at all to the game. They figured out how to get Rosalina and Luma to work and didn't mention any problems with her during the "technical tidbit" so I doubt anything is wrong with Ice Climbers at this point. Whatever problems they were having I guess they cleverly figured out. But I guess we'll see on the 24th. I think we need to hear about at least 30 starter characters before E3.
Here's my feeling with future reveals. Smash64 had 12 characters when you finished the game, so in Melee you start with 14. Melee finishes with 25 (26 including Sheik) characters and in turn Brawl starts with 21 (25 including Sheik, Zamus, and Squirtle and Ivysaur) (Im counting Charizard as the main character of that bunch cause he appears in Smash4)
So! Therefore! Because Brawl finished off with 35 (39 including the rest) Smash4 might start with 34 or 33 including a random slot, because of the nice melee like roster shape it makes with a 3x9 box with an additional 7 slots below. We have 29 characters announced now but Sonic and Megaman could be unlockable, as well as other possible unlockables like Toon Link or Lucario which I believe are just starters now (many people tend to disagree for some reason)