The new Berserker Atugia art for example doesn't replace the default Atugia art when talking to her while she's wearing her Berserker set. Do I have to toggle this?
Honestly I'm glad they don't. Most of the time the set busts don't have nude versions - Azzy is literally the exception because two of her sets are basically temporary transformatives. I'd find it absolutely jarring to go from Moira's berserker set bust, to DCL's nude bust during a sex scene - which is what would happen. I like the consistency in style.
Happy as a clam to keep those busts to icon and character sheets only - though I will say I kind of wish we could choose between the default bust and the set bust for the icon and sheet if we wanted to. I find it weird to use a lot of Cait's sets when my Cait is Leothran tf'd, for example.
It's a choice between either having busts reflect things like pregnancy, transformation, etc. or not.
If they didn't, sure, we could use the set busts all the time. But we made the choice to have the primary bust reflect the companions' actual appearance, so that means the set busts stay tucked away in menus.
TBH, I would not like to see Tui's alt art when she is talking with me. Her boobs get bigger for some reason and, it may be silly, it doesn't sit well with me...