We pretty much know what cards are the all-around favourites. Now let us see, if you are willing to share, what are cards that you dislike (playing).
I could think of many but I will start with a couple only.
Radagast I think is quite terrible. You only get 2 willpower (other stats being even worse) for 5 resources. It takes five rounds for him to pay it back, that is if you can find better use of his resources than those you paid for him. I guess in a mono-Tactics deck he can find his place but if there is a character who now needs a better second version, it is Radagast for me. Or at least he needs some great creature cards to cooperate with (Ents, anyone?). But even then you will probably be able to pay for them without Radagast's aid.
The other is the Favour of the Lady. I really like the art, to the point I was keeping the card in a deck for a very long time (given its usefulness). But it is ever harder to justify its inclusion.