Considering the current state of the game, if you limit the number of shield cell banks a ship can use, there then needs to be more combat modules. Otherwise most ships will have similar if not the same load out. There should be an advantage for combat outfitted ships over multipurpose traders, etc. A ship completely setup for combat should have an advantage over a ship that isn't, or has a balanced setup.
As it currently stands, a Pirate Player, or Multipurpose trader will have a need for Cargo Holds, where-as, the Bounty Hunter coming to claim their bounty should they be wanted, won't. I don't particularly disagree with that concept.
If shield cell banks are changed, there needs to be more combat specific modules that have an impact, even slight, during a combat situation.