I see your point Maha, as in a fleet of Cutters would have a hard time taking down a fleet of LMM's due to crew size.
I would challenge back that plundering ships should not be as easy of a task as it is now. That is why I made this suggestion.
If a new player wanted to plunder some LMM's, under this proposed structure, they would need some Sloop of War with some Grape Shot. Or they would need to build a few Frigates.
This also, adds some protection for Merchants as they can still be attacked by Cutters, just not Plundered as easy by cutters.
This idea is to hopefully get larger ships out sailing again but add some interesting battle tactics.