It might work, although it's tough because most sports-game simulator fans would overlook it.

They'd need to add more teams, more individuality in the player motions (I'm thinking of my beloved MLB the Show), more realism in the game movements -- not make it look like everyone stops and faces off for each tackle, for example. Most of all they'd need to make it more 3D. Right now, despite the sphere, it's essentially a game played on a flat playing surface; apart from very minimal dodging in Tackle Slip and the fairly unrealistic leap at the end of the Jecht Shot, there's no advantage taken of up and down.

I might get hooked. I'm not sure if it's enough to stand alone, though.