I think people are worried because of Smash 4.
A lot of the characters weren't ballot. Wii Fit Trainer, Duck Hunt, Corrin, Greninja, and Bowser Jr. Megaman, Villager, and Little Mac definitely did well on the ballots though and I do welcome a lot of the characters I mentioned too, but it felt like there was less fan input than right now or during Brawl when it came to the characters.
Ridley and King K Rool were missing. Isaac as well.
Also there the representation was weird. I love Kid Icarus Uprising, but it received so much content while F-Zero, Metroid, Donkey Kong, Star Fox, and Wario were pretty barren. Then there was Fire Emblem where a lot of its new content was just from Awakening.
Also a lot of established rules were broken. Final Fantasy had a pretty huge Nintendo precense, but Cloud? Not really. Bayonetta was a 3rd party, and while she is an icon, she wasn't Ryu, Mario, Sonic, Pac-Man, Snake, and Megaman level.
All of this made it seem like it was a mix of advertising and Sakurai's own personal tastes influencing what the game received. Also it added an element of unpredictability to the roster. For Brawl, all of the choices seemed more or less obvious besides for Snake.
Earth. The cool thing about Golden Sun is an element isn't just one note. Water isn't just water... its mist, fog, mud, snow, ice, etc.
Earth is even more diverse in GS. Rocks/Minerals, Salt, Death/Life, Ground, Sand, Plant Life, controlling animals, etc.