Long queues in 4/8 player content are bothersome and really unnecessary at this point. I'd say the best way to solve this is to add more DPS slots to this content. WoW has a 5 player small duty content setup; there's no reason FFXIV couldn't do the same. Then we could change 8 player DF content to 10. If that's not enough we could add more DPS slots until the queues even out.

I think Alliance raids are already relatively fair for DPS as far as queues go, so those can stay as is.

The great thing is that SE wouldn't even have to rebalance the content. DF is already pretty unapologetically easy, so is anyone really going to notice if it becomes marginally easier? We can keep the 8 player setup for things like Savage/Ultimate, though.