They can help mid level flashpoints by adding mentor/sidekick/level match system. Where high level players can match low level players to help them without making the flashpoint too easy or hurting their xp. This will also help with heroics where cross server LFG will not, since many heroics are not instanced. Not to mention helping people level in general and bring more people back to dead worlds.
Just an alternative solution to the specific grouping problem you mentioned, not trying to be for or against a LFG tool.