At the moment, when reviewing an edit, you do not have any indication of what others are thinking about the question, at least, not until you click 'reject'. Only then, once you are already going down the route of rejecting do you see what others are thinking. I see many edits that should be rejected but are already approved, which I assume is people rushing through to accept edits (perhaps a downside to badges, but let's not get sidetracked).
I propose that when reviewing an edit, you are shown how many people have so far rejected the edit. This data is already viewable to a reviewer, it is just one step away. Hopefully this will make people think about approving posts if others have already rejected the edit. As I see it, this will hopefully make people more willing to reject edits, and if it turns out that the edit really did need to be made, someone else will surely propose it.
I in no way pretend to think that this will make the review system perfect, but it do belive it will help towards that.