So, what you're saying is a game that lets GMs create their own MORPGs for their personal groups, sort of an RAD for tabletop RPGs. Say, the GM makes a scenario for Greyhawk Online, which has a bunch of locations and NPCs and items predeveloped. He makes a few extra NPCs and tweaks some others to fit his agenda, and sets up a few encounters. He then has his group create their characters, which uses a client that has a D20-based generation system with a visual representation and maybe a few personality traits added (many of the NPCs would be 'bots for ease of GMing, and extending that to the PCs lets a game continue with a missing player's character going as a bot); GURPS with pictures, perhaps.
Now, everyone logs into the server, which has some sort of MMORPG subscription service. Game play works something like RPGs over IRC/AIM/whatever chat system, but there is a visual representation of the game, with sound and actual spoken dialog (customized voices, not just customized pictures ... now everyone is a Real Roleplayer using a funny voice!), so you can actually see combat or NPCs, like a MMORPG. Some of the game can happen without GM input after he has used the electronic tools to create the scenario, so even he can go have a sandwich while everyone else is kicking butt.
(No, this isn't wholly spontaneous; I've been thinking about this for awhile.)