I've brought this up a few times in-game and the responses were largely positive, so I thought I'd make a thread here. I'd be happy to map this myself and submit a PR if there's interest in this.
Baystation's brig currently looks a bit like this.
The cells are all connected to a communal area prisoners can enter during their sentence. The communal area has some mildly interesting activities for prisoners during their sentences, such as botany, a newscaster, library computer, socialisation, etc. Hopefully, this keeps the prisoners engaged during their sentences and makes the brig a bit less SSD/suicide inducing. The communal area also serves as a permabrig, so permabrig prisoners would no longer effectively be removed from rest of the round.
One other feature of the communal brig I think is particularly useful is access to a cryostorage pod. This is great for prisoners, as they don't have to go SSD in their cells, but it also means that criminals can't intentionally go SSD upon being brigged and expect to be dragged out.
I suspect a communal brig on Paradise would need to be slightly bigger. This one only supports 3 cells, whereas we currently have 9. If possible, if would be very nice to move the Brig Phys office so they have access to the communal area too.