If the game becomes too easy, I guess anyone can ramp up the difficulty artificially by removing spies or heroes and playing with a weaker deck.
I don't see the fuss with Hero cards. I think most of them are underwhelming at best.T he only ones that stand out are both the 15 cards, Yen and spy card. That's it really. I mean, what's the point of the Triss card? It's terrible. The 10's are next to useless too if you, erm, well play your cards right. Throw a high normal card out and the AI will use it's scorch cards straight off the bat. When you're relatively sure it has none left and you have a horn or two, your bog standard cards are more valuable that most hero cards. Then there's the medic card and decoy cards - which hero cards ignore. I've won many a game just using my decoys to pick up my medic cards if no spies are remaining or included in that specific match.
I like to have the two solidarity 8 catapult cards (or whatever they're called) and a horn in my deck. That's 64 from 3 cards. Better than any hero card, especially if you have the clear weather leader. It's a last round winner 9/10 times