If the gaming is done to grant reputation to a sockpuppet account, then this could be handled as part of vote fraud prevention. In this particular case, the suggestor quickly received reputation due to the actions of one user, which is very similar to serial upvoting. Handling this case as part of serial voting detection would catch both cases where all the suggestions are on one post and cases where they're spread over many different posts. This would also catch the same thing done on tag wikis, where such a string of edits could easily go unnoticed.
If the gaming is done to bump the post, it's going to quickly backfire as it did, because someone's bound to notice and flag.
If the gaming is done to grant a reviewer badge to the main account, it's more difficult to detect. But that's a rather bizarre way to get a badge. Either it's done in a high-activity review queue (e.g. SO) and it's easy to find 20 naturally-occurring suggestions to approve every day, or it's done in a low-activity queue and some other reviewer is bound to notice the sudden influx of weird suggestions.
A single post with that many edits should have become community wiki anyway (why didn't this one?). 7 approved suggestions (enough to grant the sockpuppet enough reputation to vote) wouldn't do it, but an account whose reputation exclusively comes from 7 different events from the same source should be detected as part of vote fraud prevention. And there may well be cases where a single <100-rep user wants to edit a CW or tag wiki post many times (for example, the maintainer of a piece of software, who updates a tag wiki every time he releases a new version but doesn't otherwise participate on SO). So I do see corner cases where your proposed limitation would be legitimately be too restrictive. Besides this, it's an ad hoc limitation to catch a rare fraudulent case, which I think should be handled behind the scenes (à la serial voting detection) and not through built-in limits. All in all, I agree there's a problem, but I prefer a different solution.