It's not the issue of the designs because majority of franchises have so much anime influence but it's because it doesn't represent a western franchise. People want that western feel.
Look at Donkey Kong, it's best games were made in England and Texas. Metroid's jump to 3D was done in that same studio in Texas, Punch Out got resurgence in 2009 by a Canadian studio and F-Zero, Star Fox and Zelda sells more here than anywhere else.
I agree that DK and Metroid could have had more content, but the quantity of content across the two versions of the game is roughly the same as previous Smash games.
There is more emphasis on DKC Returns and Other M this time around, as is usual for Smash games to focus on the content added to the franchises between each release. Being console releases, the bulk of their content is on the Wii U version.
Brawl did focus most of its Metroid representation on the Prime series. The Prime series isn't forgotten with the addition of the Dark Samus Assist Trophy and it seems she's quite faithful to her original self in the Metroid Prime trilogy.
Meanwhile, DKCR serves as the main inspiration for one of the most unique stages in Smash Bros. history, Jungle Hijinxs, with its dual layer mechanic and going back and forth using the Barrel Cannons.
F-Zero is dead and this game barely added any content beyond what was already in Brawl, which is honestly reasonable. At the time the game started development, Star Fox was dormant as well and, aside the removal of Wolf, the amount of Star Fox series content is roughly the same as Brawl plus a new stage and a few new music remixes.
Zelda, being one of the biggest Nintendo franchises, offers plenty of content in Smash and always has done so. As a fan of the series, I am very satisfied with its current representation. With 7 stages across versions coming from different games and showcasing the variety of the series' locations and the new items added, it added a lot of iconic elements that were missing in Smash... You can't really say that Sakurai ignored the Zelda series this time around. Sure, there was no newcomer, but they did add a lot of Zelda content that, for me, compensates the lack of newcomer.
Of course, there's the whole Ganondorf moveset issue/debate/problem/whatever, but I'd rather not talk about that again.
Little Mac had people go "who?" in Japan much to us Westerners' amusement. Given it's a franchise newly added to Smash and there aren't many Punch-Out games, there isn't a lot to draw from, but there's still some music, as well as trophies showing off plenty of the boxers from the series. The arcade game gets a nod with the Wireframe Mac alt. Most of the content is actually based on the Wii game, as both Little Mac's design and the trophies, as well as Little Mac's Final Smash, come from there.
The Little Mac trailer itself also had a very Western styled presentation to it.
Obviously, with the development team and Sakurai himself being Japanese, it's inevitable that they will be more familiar with the series with more Japanese influence or that had more impact in their home country. There might be a kind of bias in this regard, even if unintentional or unconscious, but I think the claim of "Sakurai clearly hating the Western-influenced series" is quite a ridiculous notion.
I remember talking with
PushDustIn
about Sakurai's Famitsu columns and he does play plenty of Western games, commenting on them in the column (whenever not talking about Smash Bros. or any of his own projects).
(And well, I think I've rambled enough...)