My concern would be: what happens if players make suggestions and the mods ultimately say 'no'? Back in the LJ days, I was in a small game where the mods did take a couple of suggestions but turned down others for being time-consuming. The suggestions they took were good ones. But a handful of players started resenting the mods for not taking their suggestions as well, with open accusations of favoritism, while the mods were left in the awkward position of trying to explain why their idea wasn't workable.

Which isn't to say that player suggestions are bad, or all players would react this way. In some games, this might work great. But I've also seen the bad outcome on this.