The game encourages us to unlock all of the specializations, but that does not mean we want to play every last class, or have a good/fun idea for a build for specific classes. I think there is a better alternative to throwing essence away re-rolling the required specialization, or even provide an alternative to it.
The Goblet would allow us to accumulate and turn-in while staying on our current class, but each consecutive turn-in that is not the requested class could offer us 5% or 10% fewer rewards, capping at -25% or -50% rewards. This would allow those of us who have no intent of switching classes or constantly rerolling after every turn-in waiting for that 1/15 to be our class again to just keep chugging away and not waste time or resources, but simply accept fewer rewards.
Thank you for reading.