Me. I don't want to mount modules if I don't want to. I want the functional benefits without needing to add the cosmetic effects that normally comes with the modules. If I try to do something different, I have to figure out where all the modules go (some are easier to place than others).

I frequently use a lot of defense modules, so I often have to design my ships so I have room to place those modules without my ships looking horrible. Designing my ships with that consideration in mind does limit the kind of designs I make, and makes some design features common to most of my ship designs.

Weapon modules, I would like pre-select where the weapon modules go when I add them. What to do when I add an odd number of weapons (when I design my ship around the idea of being symmetrical), or stuff like that. Basically what to do when add x amount of weapon modules, what to do when I add y amount of weapon modules, etc.

Also some ship designs might have other kinds of modules installed, so I would like it if I could specify where to put them. For instance what to do if I place a survey module, a constructor module, an atlas module, a fleet warp bubble, etc.

When I bothered about ship appearance, I usually solved this in GCII by rotating the component and playing with the scale slider to make the part invisible (or mostly so). Which I admit isn't perfect.

I certainly wouldn't mind a setting that made the functional components of a ship (or selected such components) invisible, but it wasn't impossible to work around in the GCII designer, so as long as that remains true I won't complain.