More new characters in Tatsunoko Vs. Capcom

[Vipershark]

In Brawl's case, if they just announced an original starting lineup with say 3 more characters, lots of people might be skeptical about buying it because it doesn't seem to bring that much new to the table.

While the rest of your argument is sound, I disagree with this part.
Brawl would've still been the selling powerhouse that it is had they not announced the entire roster, simply based on Melee.