I honestly don't see the Sakurai bias everyone loves complaining about. Kirby got one new stage and one retro stage, and zero new fighters (though I guess if you count the 3DS version then there's two new stages). And Kid Icarus got one new stage/one retro stage, a newcomer, and a clone (and really people love to blame Dark Pit for everything but the only other clone they could have made was Alph). So okay yeah, a large amount of Smash Run enemies were from KI:U, but wasn't that just to save time by importing them? If we're going by that logic then wouldn't Sakurai have a Brawl bias since a lot of Brawl's stuff was imported to save time (and quite a bit of it was left unchanged)? Really if anything he has a Mario bias (in every game it's had more stages than any other series), although I would argue that, at least character-wise, it's fine (7 characters and 5 play completely differently, with only 1 clone and another barely semi-clone). We don't need less Mario stages since there's still so much untapped potential (Mario Party, Mario 3D World, Paper Mario, Mario&Luigi, not to mention returning stages), we need more stages from other franchises. I mean c'mon, no new Earthbound or F-Zero stages on the Wii U? Only one new DK/Metroid/Star Fox/Pokemon/Kirby/Zelda/Wario/Yoshi stage on the Wii U?
I'm also fine with the character roster we got. The stage list could use dozens of improvements, yes, but the character roster is perfectly fine. Well, okay I would probably add a DK and Zelda rep (Dixie and Impa maybe?) and bring back the Ice Climbers and Lucas, but it's not as terrible as so many people make it out to be.
And if I'm going by the various reviews I've read about the Wii U version, I'm apparently in the minority when I think that the Wii U version isn't content-packed. The new "main" 1P mode is terrible, the secondary one is similar to Event Mode, and the other minigames (and I do mean mini) are fun but not substantive enough to last very long. Add that to a mode tedious Classic Mode and a more repetitive All-Star Mode and there's not a whole lot to do in this game past the main battles (which, yes, are by far the most important thing and I do know that they spent a lot of time re-building and fine-tuning how some characters work and the overall engine but once you get past that there's not much else to do).