User blog comment:Tails365/New meta for season 3/@comment-5570995-20121011193521

The meta's "evolution" is driven by pro-players and by Riot. Since pro-players are always working to find the most efficient/most effective way(s) to win the game. And Riot directly changes the game to "guide" it in a particular direction - usually in the direction of "lets not have a 60+ minute turtle match where no one does anything".

I don't know of any specific changes you could expect to see in Season 3, at least as of right now. But since Riot is working on changing up items and "fixing" top lane, that should be enough to shake up the meta for Season 3 on its own.