guys i think that there is a possibility to include not isaac but Matthew!
I lot of people have suggested this. The fact is, Matthew is so similar to Isaac that it'd be quite pointless overall. Isaac is more important to the series as a whole, and since they ARE so similar, Matthew could just as easily be an alt of Isaac.
Also, here's a DLC poll on Smashboards:
http://smashboards.com/threads/poll-vote-for-your-preferred-smash-bros-dlc-choices.375784/
For newcomers, its K. Rool, Dixie Kong, and Isaac. For Veterans, its Wolf, Lucas, Ice Climbers, and Snake. In total, its K. Rool, Wolf, Dixie Kong, Lucas, Ice Climbers, Isaac, and Snake, but these guys have a significant lead over the rest (the next-highest after Snake at 28 is several characters at 20).
I voted K. Rool, Dixie, Isaac, and Lip of course.
Personally, I'm not getting my hopes up too high for character DLC beyond Mewtwo. What I'm seeing on this forum (not particularly this topic) right now with "Mewtwo confirms further DLC" is very similar to what I saw with "There must be more characters in the final game, because of the lock symbol on the All Star Mode". I see a lot of people getting way too far ahead of themselves.
Nothing is confirmed except for Mewtwo. The way Mewtwo was presented didn't really give me any confidence. He was represented less as a DLC character, and more as a benefit of buying both games. Him being available as paid DLC beyond owners of both games is pure speculation.
I just have this sinking feeling that's all it is... That Mewtwo is a special case.
Of course, I could be wrong... But I just hate to see so many jump on this bandwagon of things being confirmed that simply are not. I repeat absolutely nothing is confirmed except for Mewtwo.
Here's the thing. In order to develop Mewtwo, they have to keep all their teams together for an additional six months at least. Why do that for just one character? It honestly just doesn't make that much sense in the long run. Mewtwo IS DLC, regardless of how he was promoted. He'll be sold separately later, especially when you consider that the special offer of getting Mewtwo for free is only if you register the games within a limited time. They are continuing to develop and add other things into the game post-release, too, including a few game modes and even one stage (at least). Sure, other DLC isn't confirmed (yet), but Mewtwo makes it blatantly obvious that they can do so, and DLC will sell, especially for Smash Bros.
I give DLC other than Mewtwo a 90% chance of happening. Yes, it is just a number I came up with, but the fact is, Nintendo is doing DLC left and right. Smash is the big game coming out, they wouldn't miss the opportunity to do so.