Hey, I have an idea! Let's make handling illusions harder than normal!
I know the description of illusions in the original books is pretty straight-forward: GM describes what PCs see/hear as normal, but if they attempt to touch/interact with the illusion, it vanishes. But I'm sure we can improve on that simple procedure and think up a bunch of edge cases and house rules to make illusions more difficult to run. And then we can waiver in our convictions and let players start arguments about whether an imaginary cup should hold water.
If we do things that way, we can complain about how difficult illusions are to GM. Sounds great, doesn't it?