IDK about changing hull types around. As long as artillery hull type is named artillery, then plasma seige, if any type if any starship, should have that hull type.
IMO, the hull type situation needs a big rebalance anyways. I honestly think that having hull type trying to conditionally model three things (ship size, hull material, ship role) just muddies the issue, and leads to such "clustering" of hull type assignments and hull type bonuses like we do now.
I think a reasonable short term fix will be to give a few things an artillery bonus that would make sense to have it. (And maybe a bit of a health nerf for the PSS too)
For tbe long term, I hope the hull type situation can be readjustsd some when the armor situation is addressed.