Hi, I don’t Know if this already came up but since i see many Opposide the Cost of the Upgrade i thought of an Addition twist to make it (under circumstances) cheaper to Upgrade Cards…..
I’ll give a quick example using the very same card you used to announce the new upcoming fewature Razor. My idea is based on using “useless” commons/uncommons etc ….
So for example players will Choose (1 or 2) Razor(s) for the base card they want to be upgraded … then they COULD choose any card(s) for a enchancer lets say Tremor Hunter then on screen it Could say that there is a 10% of success (additional Tremor Hunter increase by 5% but only up to max 75%) + the cost in Gold, the lower the success rate the Higher the Cost, 100% success rate no Gold (common could start at 5% and increase by 2,5% and Max at 50%)
Sucess means Tremor Hunter(s) + Razor(s) gone, new Razor created plus Gold Gone
Fail means Base card stays as is but Tremor Hunter(s) gone + 50% (or something) of Gold lost
So Using lets say 3 Razor(s) = 100% and no Gold needed…..
Legendaries could need maybe only 1 base but have lower success rates.
Dont know if it is too complex (or too random fr your taste) to do but hope that i could help :)