I'd like to see a hero have a spell, or an ultimate that worked like a reverse AoE. The caster targets a spot on the ground to set a safe zone, while a large AoE around it, forcing playes to move into the only nearby spot to avoid it.
I think it would be a powerful tool to force champions to move to a location of your choosing, and an excellent tower defense spell.
This would need a limitation on it to prevent the caster from casting it near himself, I think.
The AoE could either build in DoT damage, or place a countdown in the middle, counting down to a flat damage to people who didnt move to the safe zone, or far enough away to the outside of the "Donut AoE"
There would also be a question of how large the AoE would have to be to make players consider moving to the safe zone rather than to the outside of the donut. How large is too large? Is it too large to make the spell viable without being too powerful? How large should the safe zone be, and can these thing all be tweaked to find a balance?
Anyway, just a thought!