You are always entitled to your own opinion on characters. Lord knows I have them, too. But... I at least try to look beyond my surface ignorant perceptions of a character. What you just said about Isaac is one of these surface ignorant perceptions. Yes, Isaac has the appearance of a swordsman, but the sword itself is only used in Golden Sun games for the basic attack option in battles. Isaac and Golden Sun is much more about psynergy (magic) and summons.
Besides, you claim that this final roster would not satisfy people. You are very wrong. This is objectively the best final roster in terms of what fans want I have ever seen since I've began speculating in the Brawl era. (which makes me take it with a grain of salt). Isaac, Geno and Banjo & Kazooie have been characters with major support since before Brawl (especially Isaac and Geno, I think Banjo was not as prominent because of the licensing complications), like Ridley and K Rool. Maybe not quite at the level as Ridley, but it's hard to top that. These characters have pretty much topped any attempt to recreate the Smash Ballot. The fans very much want them, and including these three characters would shoot the hype so far through the roof for the game for a lot of Nintendo fans I can't even begin to describe.
Chorus Kids and Mach Rider are more along the lines of what I'd expect from Sakurai. These are not widely requested characters, but they are believable. Especially because Sakurai always throws in some kind of NES-era retro character (Mach Rider in this case).
I still need official confirmation (or a more conclusive leak) before I will believe this one, though. It's just so good.