Increase the damage of old spark's projectiles as they travel

I think that restitution is a pretty fun and unique mythic. It allows for a new battle monk playstyle, where instead of flying around and using the high mobility from your movement spell to dodge hits and stay alive, you stay on the ground at a distance where you're safe from enemies while still being able to hit them thanks to the range that old spark provides.
The problem is that at range, none of your spells other than war scream's air shout will hit your target so you miss out on a lot of DPS (using more uppercuts isn't an option since you'd lose the damage from pressure and harmony).
To counteract this, my idea is to make the damage of the projectiles increase with distance traveled (you could also increase their size and speed a little along with their damage for a bit more oomph). The negative walkspeed on restitution would balance the fact that you can deal damage at range, especially since you can't fly around like with other battle monk weapons.
This would also work as a crosspath for fallen builds. The extra surivability you get from the range would be balanced by the AP investment you need to get whirlwind strike.