Mario, Zelda & Pokemon are Nintendo's biggest mascots so of course would they be more dominant in the character rooster.
But this Direct was really 50% just about Pokemon, 25% about stuff that is actually interesting and 25% about stuff we already knew about.
I don't like Wii Fit Trainer either. I mean has anyone ever cared for him/her, ever?
The argument that he/she fits the tone of SMB is pathetic. We might as well take one random unrelateable NPC character from any Nintendo game ever and slap him as a character in SMB just because he hits the tone.
The Direct contained one minute of footage regarding the Pokéballs and then at the end there was the trailer for Charizard and Greninja, which lasted about two minutes, so it was hardly 50% Pokémon. The Pokémon part just stood out, because it had a fancy cinematic.
As for your opinions regarding the Wii Fit Trainer: different people care about different characters. I personally don't really care about Lucas/Falco/Diddy Kong/a few others, but I'm fine with them being in the game as long as they're unique (which a few weren't in Brawl *cough*FalcoFoxWolf*cough*). So far the Wii Fit Trainer seems different enough from the rest, so I don't mind him/her (that doesn't mean I care for the character outside of Smash). I do think that they shouldn't include too many less popular characters like the Wii Fit Trainer though.
I wished they put the characters that didn't make Brawl into this game, but noooooo, they probably won't.
I'm pretty sure they planned the Villager to be in Brawl, but he was dropped. So some characters that were dropped for Brawl might still make it into Smash 4!