Seems like a fairly standard and safe roster. I don't necessarily think that there is anything wrong with it. My only problem is with four 3rd party characters. That is more of a personal bias though. I tried to rationalize how 3rd parties are going to work in the franchise. So don't get this wrong. I think the roster is great. I actually think that Lucario will return, and I don't think Shulk is going to be in the game. Those are the only two things I would change. However, I am betting against 3rd party characters. Perhaps somebody can analyze my logic and assess any discrepancies?
I do not think Sonic or Snake will return for Smash 4. Here is why... lets us evaluate how Sakurai treats 3rd party characters. There were no 3rd party characters in his original entries, Smash 64, and Super Smash Brothers Melee. The first game to include 3rd party characters was Brawl. One at the behest of a friend, another due to sheer fan popularity. This time around we already have Mega Man. He correlates to Sonic. He was added due to staggering fan request. We do not know any other 3rd party characters that are going to make it. Most people assert that Sonic and Snake will make a come-back. Others think that Pac-Man has the connections to secure his imminent roster slot. This leaves us with 4 characters.
That isn't so bad. It seems reasonable currently. However, we must look beyond. Smash X is what I will refer to the Smash after Smash 4 and 5. This gets into some subjective territory as Sakurai might not be the creative director on the next project. So a vision change might occur. However, for the sake of discuss, let us assume that Sakurai is on board for Smash X. This is where problems start to occur. Sakurai likes to treat 3rd parties as a special case. Sonic and Snake were both special. Now Mega Man is considerably special. How special would Smash X be if he continued the pattern and followed precedent (for arguments sake assume we get Pac- Man and Mega Man for Smash 4)? This enables the Smash universe to have 6 third party characters.
Obviously 6 3rd party characters is borderline ridiculous when we considering that Sakurai already believes that the roster is feasible currently. At this point, the 3rd party characters will literally be taking up Nintendo roster slots. This isn't at all what Sakurai would want. In fact, I think Pac-Man falls under the "Snake" rule. We might get him in Smash 4 only because of Namco's association and involvement. So Pac-Man in Snake are more like favors or obligations that Sakurai has. Mega Man and Sonic are the 3rd party characters that the fans WANTED, WANT, and WILL WANT. So it is very possible that he might just cut off obligations and keep the 3rd party characters at two per entry (meaning 2 in Smash 4 probably Sonic and Mega Man) and keep the two during Smash X.
It is this logic that leads me to believe that he will drop the 3rd party characters in Brawl in favor of two new 3rd party characters. That helps Smash feel fresh. If Sonic were to be revealed, he would probably be revealed in October. Pretend you are Sakurai. Would you want to take away from October by revealing Sonic after the launch of X and Y. Probably the biggest handheld game of the year? It doesn't seem logical. I guess he might. I wouldn't though.
I apologize for any errors. I just woke up and I was pressured to wrap that up quickly. I have to go help with something. So I didn't have time to fix everything. Just leave me your thoughts on 3rd party characters. I really want to read what people think. I feel like it is a subject that we skip over. We take the easy way out and assume that there is no way Sonic will leave. Or Pac-Man is guaranteed because Namco is co-developing. It is a touchy subject that tends to illicit menial and simple responses.
TL;DR
Jigglypuff