Honestly, the best way to play is with NO FREE AGENCY. It forces GM's to trade if they want to better their teams. I play in two leagues set up this way and it makes FF much more fun and challenging.
1) Start the season off with expanded rosters (18-20).
2) Somewhere around Week 4-8, host a supplemental draft of three rounds to pick up sleepers like Anquan Boldin that everyone missed in the preseason draft. Worst team picks first...no snake draft on this one.
In the end, each team has a roster of 21-24 depending on how you want to do it. If you can get this into a 12-team format, it is fun as hell because people will definitely have holes in their lineups as injuries occur. None of this pansy-ass waiver wire business, only trades or supplemental draftees can help your team out...otherwise play through injury with your bench.
Try it out next year and I guarantee you won't go back to enjoying free agency.
Of note though, if you have this setup with a bunch of GM's who get disengaged with the season fast, it is sure to be a real yawner...for active leagues only!