I just saw (it's approved now) a suggested edit that appeared to just be retagging - adding two tags. The user who proposed it actually had enough rep to retag questions, but presumably didn't realize there was a hidden retag link by the tags, and simply clicked "edit".
Perhaps suggested edits could be automatically applied if they're actually just retagging, and the user has the necessary rep?
Note: I'm not suggesting that reputation be awarded, just that the "suggested edit" be turned into a plain ol' retag.