I do not like the 6-3-3 format. There's too much possibility for injury or other fluke things to knock a team out of the medals. Take Russia in 2007 and Semenova's run into the vault table that dropped Russia from third to last. Or the USA in 2006 - what if Memmel couldn't continue after her shoulder injury (and if it were anyone else with that injury, she would have been out, the USA was lucky it was tough-as-nails Memmel)? The USA would have been last place.
I also dislike that the qualification requirements are different than what's used in the team finals. For the USA it doesn't matter, but for the bubble teams, they are forced to decide whether to construct a team that is good for 6-5-4 and will make finals or a team that's good for 6-3-3 and risk not making finals for a better overall result.
For those of you who want to see more than just a team's top two gymnasts doing most of the routines in finals, 2010 should make you happy with the new 5-5-4 in prelims and 5-3-3 in finals.