It’s always a bit disappointing when you have spent lots of time upgrading an item only for it to end up with an elemental bonus that has poor synergy with the item (especially given the rarity of shards for upgrading from 6-15).
It would be good to have an item that allows the element of a piece of gear to be changed (or allow a follower, eg Grungli) to do this at a cost at high levels.
For balance reasons such items/features could be rare/expensive.