No 3 slot shotgun?

Let me start out with yes I know the auto 4 is 3 slot, I mean full sized shotguns.

Overall I think the new loadout system is a step in the right direction, just there’s one part that makes no sense to me.

How does it make sense that every shotgun is 4 slots where some insanely powerful rifles are 3 slot? You could run a bethier with a specter compact with no quartermaster but a Romero with a vandal needs quartermaster? I feel like this almost kills full sized shotguns. Maybe I’m missing something here what are y’all’s thoughts