When I run a report, e.g. Top 5 Opened, my top 5 opened campaigns are some test campaigns sent to a handful of test recipients.

Not useful at all.

Sure, I could go and delete some of those campaigns, but instead, would it be possible to set the report to include only those campaigns that have, for example, 50 or more recipients?

In that way, all my reports would be more meaningful and automatically exclude the test campaigns.