Having spent a lot of time on the PTR, I feel the current gem fail/succeed upgrade system is very flawed. It does not lead to ideal game play because if we ignore the rift key dupe the most efficient method to upgrade gems is to get a trial rift key stone, fail on a trial wave that corresponds to the tier level you that takes you to about 15 minutes to complete (if you want to purposely fail a lower tier, you have to wait for the 15 minutes timer to run out to fail anyways). Purposely failing a rift over and over again just isnt fun. It's also pretty frustrating when try to upgrade and the upgrade fails.
What I purpose is an experience system for the gems. Where regardless if you fail or succeed in a tiered rift you get exp that goes towards the gem of your choosing after the rift guardian dies. The higher the tier, the more exp gained. This leads to you actually wanting to complete the rifts and move on as high as possible as well as removing the frustration of failed upgrades. Another bonus is that this can serve as a soft cap for the gems in that the higher the rank the more exp needed per rank upgrade if Blizzard wishes to go that direction.
just have a small percent chance at upgrade upon completion of the rift in the set time... so if you succeed you get a bonus chance say .. 10-20% to upgrade. hell the % chance can be tied to the rift level ... if you succeed at lvl 1 (duh) you get a 1% chance and the like lvl 11 grift key.. succeed there and get the say lvl 17 grift key and a 11% chance to upgrade..
What I purpose is an experience system for the gems. Where regardless if you fail or succeed in a tiered rift you get exp that goes towards the gem of your choosing after the rift guardian dies. The higher the tier, the more exp gained. This leads to you actually wanting to complete the rifts and move on as high as possible as well as removing the frustration of failed upgrades. Another bonus is that this can serve as a soft cap for the gems in that the higher the rank the more exp needed per rank upgrade if Blizzard wishes to go that direction.
the catch could even be that your gems only get exp in grifts.
this would keep normal rifts relevant as your only way to Get grift tokens