One of our biggest struggles is getting people to actually read the stuff that they're supposed to. Along those lines, in my company, this might be a tool that will make users less engaged in the proofing system. We actually want people to manually go over it and provide a manual approval.
FYI Proof HQ has the ability to track changes within the tool. If you use the track changes tool it will pull up 2 different proofs, side-by-side, and it will highlight the differences in the artwork, you can even specify which color you would like the changes to be highlighted in.