You realize they did a whole ton of Mechanoid rebalancing for b19 right? So this suggestion is completely pointless since you're basing it on an experience in a former version.
Edit:
Not to mention that "Rough" is no longer as easy as it was in b18, so that gives us a false impression as well. If you have this level of wealth and colonists on Rough in b19, surely you will end up getting 10+ mechanoids attacking your base, and they will tear through your defences like a fat guy tears through a cake.
Edit:
Not to mention that "Rough" is no longer as easy as it was in b18, so that gives us a false impression as well. If you have this level of wealth and colonists on Rough in b19, surely you will end up getting 10+ mechanoids attacking your base, and they will tear through your defences like a fat guy tears through a cake.