A nifty feature to have would be a Gameday Five, as in the best five players of each given gameday, nicely presented on an extra page. Probably not too hard to pull off.
Another, even niftier feature would be something like an inter-league All Star Game, maybe on the day after the regular ASG. A league's All Star Team would feature the best 5+7 players from a league, or the winning team of the regular ASG, going up against a neighboring league's All Stars. And here's the kicker: the All Star Team that wins will be rewarded with +2% of ad income for the remainder of the seaon. It's half a season with a bit of a bonus - not so much that gives the economy another kick in the groin, but enough to make a league's managers rally around their league's flag.