I think the lack of the Brawl-style Adventure Mode is really helping Sakurai and team add as many characters as possible in record time. Just like in Melee when Sakurai and team had like 2 years or less of development time.
I do think, however, that making 2 games at once will be a detriment to the roster size, but hey, at least the characters seem to play the same on both games (albeit the physics look different).
Still, it won't take up like 70% of development time like that piece of crap SSE did.
Had expectations been in check with Brawl, I don't think half of the problems would have existed with the characters selected.
I honestly think not too many people gauged the impact of the SSE to be fair, and it's easy to understand why.
Still, a lot of the people were expecting like 50 characters back then. That's nuts (well now it isn't). I know my expected range was 40-42. I wasn't too far off, and seeing as how I was expecting most of the Brawl newcomers (obvious picks), my predictions were pretty accurate.
BTW, my expected roster number is 48-53, more specifically, 49-52 (including transformations obviously). That seems reasonable.
My actual "dead on" number is 51 characters, but that's based on a simple formula. The formula is Melee had 14 more characters than Smash 64, Brawl had 13 more characters than Melee, and thus, Smash Wii U and 3DS will have 12 more characters than Brawl. 39 + 12 = 51 characters.