Really, nobody knows who Nariko, fat princess, Spike, Toro, Generic Killzone guy, New Dante, Cole, Raiden,
Nobody remembers or cares who Sir Daniel, Jak, Ratchet, Sweet Tooth (even back then w/e his vehicle, nobody cares about him), Sly, Parappa, are anymore, and even more don't even know them.
When people think Big Daddy people either think "oh that guy from that PC/360 game that didn't come out on the PS3 till like 2-3 years after, why the heck is he a playstation allstar". or "Why is there a guy in a diving suit in this fighting game?"
So that leaves what Kratos, which yeah is fairly well known and people would want to play in a fighting game. Hitachi, who is also well known from Tekken, and is suited for a fighting game obviously.
Nathan Drake, who's games are very pretty popular but character isn't really, like Marcus Phoenix from Gears, everyone knows gears, but people don't go wow Marcus Phoenix I Love him he is a great characters I would love to play a fighting game with him in it. Same thing with Nathan, tons of people play uncharted, but they don't play it for Drake.
And then finally Sackboy, which is fairly well known I guess but people don't really care about him, as LPBK showed.
They should have gotten MGS 1 Snake not raiden, DMC 1 or 3 Dante not dmc dante, a Resident Evil char like Jill, Chris, or Leon. A FF char like Sapiroth or Croud. Crash, Spyro. They may not have saved the game but it wouldn't have flopped as hard with them.
Lol while I agree the roster could use improvement, I acknowledge that characters cost money and SuperBot needs to prove themselves before companies are going to even be willing to sell their rights for certain characters.
With that in mind, this roster is more than fine.
Your analysis of each character and whether or not it belongs (and people care about it) is just terrible. Nathan Drake is not a character people care about? Sackboy? Do you even own a PS3?