Make Sightstone's Give Bonus Experience
Jungler's get bonus experience from their jungle items to prevent them from being under leveled, so supports should get bonus experience from sightstone to stop them from being under leveled.
This would work because support is the only position other than jungle that has an item specific to the role, so other positions can't abuse it.
Here's how I imagine it working.
Unique Passive - Being near a minion's death without dealing the killing blow grants 5-10 Bonus Experience.
Would require something a little different because it lets you kill minions, but the idea's still the same.
It would grant more experience the farther behind in levels they are, and grant more experience as the game goes on, because the amount of experience required to level up increases with each level.
That's 30-60 bonus experience per minion wave. Junglers get 15 bonus experience per large monster killed with tier 1 jungle items 
and 30 bonus experience with tier 2 
. Most junglers can clear 2 or 3 camps per minion wave in lane, so it should be about the same.
This is a good idea for a few reasons
- Prevents supports from being under leveled, obviously. Right now supports are usually 2 levels behind everyone else by 20 minutes in, and it only gets worse the longer the game goes on.
- Since sightstone would give experience only when you have it, it would encourage supports to rush it just like how junglers rush their tier 2 jungle item. Some supports put off buying sightstone in favor of getting other items like FQC, Boots, Catalyst, etc, but if rushing sightstone meant leveling faster and getting the increased base stats and damage or utility in their kits that comes with levels, then that's a huge incentive to rush it as their first item.
