I think an interesting toggle aesthetically could be one to display roofs. We see them when we first build a room, but what I think would be nice is if roofs are always visible but become transparent (or maybe just disappear) when colonist enter them or you hover your mouse over the room. And if people didn't like it it would be possible to toggle it, I imagine. Nothing game changing, just something I think could be nice.
I'd agree less for aesthetic reasons but for functional ones; sometimes it's important to know where a roof is, and it's not always completely obvious over a large area. Being able to toggle an overlay that shows roofed areas (preferably differentiating between natural and constructed) would be useful.
I've seen plenty of people (including myself!) who didn't notice when a roof was auto-constructed, and didn't understand why crops that used to be growing just fine suddenly died. turns out, sunlight is important. so I agree with this feature being put in the game. it might look nice, and it might just save someone's colony.