re: losing points for unknown characters
Actually, I can both understand and agree with losing a few points off a score for having a lot of unknown characters. The problem lies in the title and, moreover, the title's history. The X vs. Y games have a history with familiar properties, namely Marvel and SNK. I know that SNK wasn't and probably isn't especially well known among the general gaming populace, but a good portion of gamers, especially fighting game fans, at least knew who SNK was even if they weren't familiar with most of their characters.
Tatsunoko, on the other hand, is a complete unknown entity in the west. Sure, most of us older folks remember Battle of the Planets/G-Force, but they were never associated with "Tatsunoko" in the west. And outside of them, the only other Tatsu properties that are well known are Speed Racer and Samurai Pizza Cats, neither of which are represented in TvC. Some OG anime fans might remember Hurricane Polymer, Casshan, and Tekkaman, but these aren't known on the same level as, say, Doctor Doom or Spider-Man, or even most of SNK's Fatal Fury/KoF characters among traditional videogame fans.
So as far as the west is concerned, this is Capcom vs. G-Force and.... Who the Fuck Are These Guys? I can agree with taking off a point off the review for that.
I also think the "WTF"-ness of the crossover is responsible. The ideal thing would have been to build up Tatsu's familiarity with the audience over a couple Tatsu-only games, like how Capcom warmed up audiences to Marvel characters in fighting games with COTA and MSH. Then this crossover wouldn't be seen as so left-field with so much of the cast completely unknown to us in the west. But oh well.