Every successfull mmorpg nowadays have atleast 1 always relevant activity per day to keep players constantly playing and thinking about the game.
I always thought additional server with like 4-8X the speed of current would do.
Other solution might be additional tournaments like you suggest. Maybe make every week new tournament which starts to the loosers, of other tournaments, so any team at any given time participates in atleast 1 tournament.
Also additional tournaments for league/conference winners would be nice, especially international ones.
You dont need to have prizes for wins, most people would battle for the trophy alone.