I agree with this. I think there are three major problems with the Relic Shield line at this point: number one, it's the only support income item that specifically relies on allies playing well in order to work, and it does so by having allies do something they normally wouldn't do, i.e. hold off on CS. This leads to the support getting screwed over when allies farm absent-mindedly, which is especially common in uncoordinated games. Number two, it's an item line whose passive only really makes sense in lane, because after the laning phase the support is usually expected to go out and ward, not join their allies to farm (and if they try that, the waves are usually cleared before they get there). Number three, because the item line's balanced heavily around team coordination, it's affected it to such a degree that it generally feels awkward to use in pubs, while being so good in pro play that even the marksman will sometimes take a Relic Shield as well at the start.
Because of this, I think it might be better to give the item a buddy mechanic as with Taric's W or Knight's Vow, so that both players get to share gold from their minion kills, to at least some extent. It might even be worth sacrificing some of the item's other bonuses, such as its heal or passive Gp10, and adding conditionals to prevent overlap with Ancient Coin, such as a short leash range that increases with game time, but otherwise it could help smooth over the item's problems, while still encouraging teammates to coordinate.