So you don't play in open? It isn't worthless when getting through a pack of hostile players.
Whilst I cannot help but agree she is a wonderful Blockade runner, learned that in the Lugh War running Imperial small arms to the Federal Army in Khaka; that the Lakon Type series 6 and 7 should be the "most cargo for the pad" seems to make sense from an in game persepctive as their market niche.
Having the Type 6 being the cargo box you squeeze into a small pad and the Type 7 being the cargo box you can just squeeze into a Medium Pad.