The largest sections one the flag review page are currently close question flags and low quality flags:
There are review queues that are used for the same sorts of questions.
I know posts are put into these queues by different means: the flags queue, of course, is from flags, and the review queues are populated from close votes and low quality posts. That said, both queues have the same sorts of posts that warrant the same sorts of actions.
IMO, the new review queues are much more pleaseant to work with, so instead of duplicating the same effort on two different queues, could we merge some these flag review pages into the review queues?