Not sure if this has ever been floated around, but I think a power set that focuses around projectiles could be something that would appeal to a lot of users and could easily work within the game's current mechanics (perhaps leveraging some of the animations currently used for Martial Assault).
This would be a set that focuses solely around being able to throw items at enemies. It would work really well on characters whose themes were less focused on flashy energy powers and suited well for natural origins.
Weapon customization could be darts, knives, baseballs, firecrackers, boomerangs, rocks, etc. Some of these could have secondary effects that could be borrowed from tactical arrow (poison-laced, exploding, etc) and suited well for ranged attacks.
