When I review close-votes and come along an Off-Topic-question, I like to leave a flag for the mods to migrate the post to an other StackExchange site, if appropriate and if I know one (which is okay according to: Is flagging for migration acceptable?).
The problem is, that in the review-queue, there is no "Flag"-button. So I have to close as off-topic, hit "back" in my browser to get back to the question, click it's link and flag it there.
Simply adding the "Flag"-button either in the top right corner (next to "Close", "Next", etc) or down below the question tags (like on the normally question pages) would speed this up.