Even if it wasn't full stereo, having it loud in a room coming out of 5 or 6 speakers n being "surrounded" by the pinball machines audio coming to your ears from all directions (espescially behind you would be very cool n would instantly tickle the happy ear sensors of the brain if u know what I mean).
Attach to FISHTALES and you have my worst nightmare
Yep, some machines sounds you just don't want to FILL the room :-)
Another issue to be addressed is when you have a large collection of machines, you'd need the multi-channel audio from each machine to either be connected to a switching box so you can assign a certain pin to the surround speakers, OR, feed all machines into a large external mixer (5 channels x 10 machines is a 50channel mixer, or multiple mixers.....messy).