Very interesting idea. I think the %'s would need to be tuned to some degree but it could be interesting.
Another thing I’ve thought about is a way to rip boons off the tool and restore either stability or vigor or both. They could be expensive, and powerful but provide an option for those of us who strongly dislike gambling. Maybe it costs 1 of each trophy to craft 1 of them or something. Or 50 hopper eyes
Another thing could use chill shards and freeze all but the last boon.
Lots of potential. I tried to keep my recommendations to adjustments to mechanics already in game, since the BL devs seems to prefer tweaking numbers as opposed to new additions (judging from the tool update and the previous set of balance changes) but if they are up for adding new things, I’m on board with that and would be happy to do some more testing.