After playing some games with 2nd edition cards, the one I most underrated was Patrol.
For example, we were playing a 3-player Mountebank game without trashing, and I thought, gotta be a slog, right? Patrol seemed like it could defend against curses, but it was also awkward that it reduced the chance that you'd have a curse in hand next turn to discard. Anyways, one player skipped Mountebank and built a passable engine out of Patrol. I've seen this a few times, Patrol is great for making engines resistant to junk.
I'm also impressed by Bandit. I had never really played one of those games where Thief dominates (my group knows better than to think Thief is good), but now I've played a couple with Bandit. After losing the Bandit war badly in 4P, I had to go for a Poor House / Royal Carriage strategy, which was hilarious but not very good.