Ultimately, I think that so few people change their suggestions after a review vote that the system is ok how it is. It can be abused but so can a lot of things: there are flags, and moderators with the ability to manually suspend people to handle situations like this. And any edits that are rejected despite being improved would not be a problem for good editors, who wouldn’t be on the verge of not being able to suggest a new edit like normal.
If we did see a larger problem emerging here it would make sense for an approve vote to block further changes, which would prevent anyone from vandalizing a theoretically good edit.