Seem that if I try and upvote more than one comment too fast I get the warning about having to wait five seconds, or if I leave a comment I have to wait fifteen seconds between them. Why doesn't the suggested edits queue put a similar wait on clicking through on "approve" clicks? Looks like you can easily just click away (intentionally or accidentally) and rapidly approve suggested edits without any kind of limit.
There should be already a delay when reviewing suggested edits too fast. In I see the posts I review more than once, one of the developers says:
If many reviews were performed by the same user in a short period of time (as was the case for you), a fraction of them were invalidated. Then, those same tasks were given to you again, since you were no longer considered to have reviewed them.
This is fixed now: if a review would be invalidated, the buttons are instead temporarily disabled on the client, making it much more difficult to submit a review too fast.
There isn't a dialog box that appears when you click on the buttons too quickly, but the buttons are enabled with a delay.
When I review posts, the delay is noticeable. I cannot click any of the buttons too quickly. The delay is less than 5 seconds, and it is probably enough for avoiding I review too much posts (basing on the criteria they used for "too much reviewed posts").