A few variations of beds, trunks, shelves, banks, chairs, tables would be nice (there are a number of chairs, tables and banks imported from Hexen II / Heretic II so those are not necessary), as well as some doodads to put into and on those pieces of furniture like pillows, plates, mugs, cauldrons etc.
Poly counts don't need to be high, I'd rather have a dozen of these objects in a room with a less chiseled look then on per room with high detail. Actors are still low-res sprites so too high detail 3D models would look out of place anyway.