That's grossly unfair. Sports games aren't the Rodney Dangerfield of gaming, casual games are.
Sports games are the Andrew Dice Clay of gaming.
But seriously, folks, you want to get some respect for sports games?
Roster updates as DLC, with prices to match.
Separate titles for separate game styles, ie casual, action, management. Don't try to shoehorn a couple of different game styles into a single title.
Take your time in engine/title updates. An earlier poster suggested two years, sounds good, more or less.