As it stands I consider thorns one of the single most frustrating cards in the game, it's far to much of a trump card and one that is best mashed out for that frame 1 play. I think it's one of the least strategic debuff cards in the game even, but it also combos with already strong very meta cards, but not in a funny or interesting way they just totally lock you out from playing cards by often taking a 10th of your health away with no counter play besides getting off a lucky counter card.
My recommendation is to make it control card scrolling rather than playing. So you can play a card in order but if you scroll the thorns rip at you and get knocked off the cards. I think this opens the door for more strategic plays from both the people playing and getting hit by the card and more interesting combos especially with garbage day. It'd make it more useful later in matches to trap people while they're hand hunting but still give room for cards to be played without throwing shootouts.