If people thought NASB - even pre-Garfield - didn't have enough characters at 20, there's really no chance in hell another platform fighter could challenge Smash popularity-wise. There's absolutely character libraries large enough to challenge Nintendo's (in fact I'd argue Nintendo's character library is actually pretty unimpressive, and if it weren't for Smash most people would just think of them as "Mario, Link, Pikachu, and uhh... Dr. Kawashima? Do they own Mega Man?"), but even with an AAA budget, launching with 50+ characters would be a real task without existing concepts; assets; and animations.
That being said, challenging Smash quality-wise isn't hard at all.
They should use the Super Bowl to showcase Superb Owls instead.