D, people want "niche, obscure, dead" characters in this game is because they're nostalgic and if PSASBR is supposed to be a true reflection of PlayStation's history, guys like Ico, Wander, Dart and to an extent, Crash & Spyro (yes, yes... 3rd party dilemma, I know) should be in.
Not going to lie, the roster looks pretty badass as it is right now but it's also a bit of a kick in the balls to those who have been PlayStation fans since Day 1 when there are unexpected 3rd party characters from recent-ish games getting the nod before some of the classics. I'm still uber keen for this game regardless, so it'll be interesting to see how it all pans out.
Isaac, Shulk, Toad and Pac-Man for Super Smash Bros 4!
D. People like characters the same way others do. If that character so happens to be "niche" it has nothing to do with going against the grain or nostalgia. A good character is a good character. The only thing that change view on a older character is the outdated gameplay. Which has no effect on what that character would be like in this game.