We do need some way to allow higher level gatherers to get more shards than they do. Reducing GP cost on Wards or a trait to increase yield, breaking down crystals and clusters, converting fish, something.
It would be a mistake to think that making higher level gathering of shards easier would greatly hurt the RMT farmers though. People have caught RMT's speed-leveling practically 1-50 in 10 minutes with some classes so I would assume they can blaze a gatherer through as well (even just plain farming materials the old fashioned way using teleports to speed it up). I believe they will continue to game the system efficiently until SE really manages to crack down.