As others have noted, blocking edits that are too large can prevent legitimate edits from getting through. Example
The real issue is the one described at Improve filtering of spam suggested edits. Spambots have recently learned to make suggested edits to Stack Exchange post, and there's still some work for the SE team to do to detect and reliably block spam suggested edits without risking false positives. For now, human reviewers will handle this issue, and this is why we have the review queues in the first place.
An additional thing I've noticed is an email address in the edit summary. The spambot is probably treating the edit summary field as though it were the email field in the comments form of a blog post. We should reject suggested edits with edit summaries that that consist primarily or entirely of an email address.
