Personally, I'm happy with the current known roster. Shulk was really the only one I wanted left, moreso because I want more representation for fresh blood, and also because not having Xenoblade music would be a damn shame.
The other additions [spoiler]Bowser Jr., Duck Hunt Dog, Doctor Mario, Dark Pit[/spoiler] I don't personally agree with, but they don't really make me angry or anything. I've come to the realization that Smash roster leaks tend to be really disappointing, not just because characters people wanted didn't make the cut, but mainly because the characters weren't interesting enough to make a hype reveal for (hence why they're saved for post-release) which explains why they're "meh" on discovery.
There are 5 slots left, and a leaked image of locked All-Star Mode means there are definitely more characters left. Whether they're missing vets [spoiler](Ice Climbers, Lucas, Wolf, Snake, Mewtwo)[/spoiler] or entirely new characters remains to be seen.
Personally, I just want to see alternate colors and costumes. I read somewhere that [spoiler]everyone has 8 colors/costumes and that Bowser Jr. alts are the Koopalings. That really sounds like a stretch, and also weird since there would be announcer name changes, but that many alts for every character would get me stoked.[/spoiler]