I see the point about the art shining through in certain lighting conditions, but if you were shining onto white parts (black parts?) it should work pretty well in any lighting conditions, right? I'm just thinking that you wouldn't do anything where all of the art is projected like they did (or analogous to P3), but indicators and GI highlighting would still let you not only save tons of wiring under the pf but also, as they did, add easy text and graphics to tell the player what to do without taking their focus off the pf.

Are they lasers or can the same effect be done with just a bright projector?