I think you've pretty much covered everything you'd like given the space available. You have a comfortable viewing area which is easy for kids 3-100 in age to access, a bathroom, lots of accessories to add visual interest, and the ability to run 3 trains at once "hands off" if you're entertaining "non-hobby" folks or run prototypical ops if you want to have an operating session with hardcore hobbyists. As long as you add cup holders on the fascia you're set to go!
-Greg