No, it's just basically 3 standalone seasons (and that's in casual season, I haven't tried competitive). This game is based off of the first SNES Tecmo Super Bowl, which itself was almost identical feature-wise to the NES version.
BTW, "casual" season is a bit of a misnomer - it is the same type of season mode the old games have, where you can set MAN/COA/COM/SKP control for all teams at any point in the season. In competitive you can only control one, and that's because your progress is tracked and posted on a leaderboard.
I decided to get it for PS3, but I haven't played enough online games yet to really judge it. It didn't seem totally unplayable to me though - I could feel a slight lag as the non-host, but I was still able to control my players well enough.