I also really support the option to downgrade nymphs. I have never upgraded my nymphs, but I understand those, who did.
Normal cards needn´t be downgraded and rares - I kind of like it that an won upgraded rare will never become an unupgraded one - the small "down-side " of winning an upgraded one.
Downgrading nymphs shouldn´t cost anything, that would confuse noobs. "Upgraded cards are better than unupgraded, and I should pay for downgrading ?"
Either 0
back or 700
, that´s the exact difference of the upped and unupped nymph sell prices = (1600+x)-(900+x), x = quanta cost of nymphs.
Not more than 700, then downgrading + selling would be better than simply selling. (But NEVER dare to sell nymphs ! Selling nymphs is never good).
