Idea for a passive for a support
Otherside Collector (Passive) [this champion] doesn't get experience from enemy minions. Instead each friendly minion that dies on the map drops a soul which can be picked up by [this champion] walking near it and giving them a stack. This rewards them with 65% of the experience of that friendly minion. Souls last for 5 minutes.
What does this actually do? The support is not sharing the experience with their carry for minions, so the carry is getting 100% of the experience. The support is collecting souls which give them a separate amount of experience, about 5% better than the support would normally get when using shared experience. The support does not necessarily have to roam but they could roam and collect the souls in the other lanes to continue gaining experience. Roaming also means you are not taking the minion experience from the other lanes when you come over to gank.