Didn't you ever wish for that feeling of stomping hordes of somethings under your feet? How about being a lone survivor against the hordes? What about part of a massive army in a gigantic conflict?

I suggest that you can set your own facts for the Demigod campaign. Global things like amount of enemies, size, health, respawn, speed, and the same for friendlies. This could be an unlockable. So after you're done with the Demigod campaign "TWIMTBP", you can effectively build your own scenario by altering these values. See Goldneye 64's 007 mode for the example.

So, for the above examples, if you feel like being some giant-ass stomping on ants, you'd become the Rook, and make yourself super-sized. Then turn off friendlies by setting their respawn to 0, and turn up the respawn rate of enemy creeps by about 50,000%. Maybe some attack speed boosts? Or, you could just turn up both sides respawn rate and model size to make it a much more epic battle. Now you can play the campaign the way that you want.