God, so many infinite combos...
Mining Village, Raze, any other self-trasher with Champion or Adventures tokens (Death Cart, Pillage, Engineer, Treasure Map), Procession is maybe not infinite but certainly absurd, Apprentice is crazy, Rebuild is crazy, Bishop is pretty crazy, Salt the Earth is disgusting, Lurker is disgusting.
Although, in the absence of these cards, and the presence of more reasonable trashing like Remodel variants or other TfB, it seems pretty fun, but those seem like a minority of boards. I assume that's why Fortress is a village; to make it so you want it even if its below-line isn't relevant.
I think you could fix the worst problems by making it "the first time each turn that you trash...", though that doesn't fix Salt which is probably the worst non-infinite combo. Maybe you could also word it like Market Square, where the trashed card has to be YOURS.