We recently had suggested edits that only had the purpose of completely replacing the post content with nonsense, such as in this case.
Such edits, where the post is completely changed, should be rejected automatically, without even appear in the suggested edit queue. Suggested edits should make the post clearer, not changing it completely, which is what the suggested edit is doing, if it is keeping very few words used in the original post.
The control should be done for posts with a length higher than a minimum value, and when the modified text is at least 80% (or 90%) of the original text. I would let a user review the proposed edit, in the other cases.
Once the user's reputation reaches a specific value, this type of control should not be done anymore. The control should probably be stricter when the proposed edit has been done by an anonymous user, for which there isn't an account to block, in the case the user keeps defacing posts in some way.