again, just because all these MMOs are huge flops doesn't mean that the MMO format is flawed. It's just that the content is complete crap.
Imagine a game that combined the best aspects of an RTS, a FPS, a RPG and was MMO at the same time, all set in a compelling environment (realistic, yet futuristic, similar to Killzone or Halo 2, or cross BF2 with America's Army with Ghost Recon 3 with Planetside/Halo 2).
Make a game with a realistic/futuristic FPS with large scale RTS elements for the 'commander' types, and add in rank/equipment earning through XP (similar to Planetside) for the RPG elements.
Planetside is a good game as far as it's overall ideas. It's the execution that's complete shit.