MArcomage

I kind of dislike the combination Quick and Durable for a common card.

I agree, especially since it has such low cost.
Also I think it is kinda too powerful giving the opponent -1 Tower per round per card.

I've changed it raising the cost. and now it damages only the wall. I like it with the combination "quick, durable, no effect if new": in this way you must wait 2 "turns" to play it again. It could be uncommon but it will be harder to discard with banish.