Hah! You're right. Winter throws the gold curve so that Flank isn't good. Suffice to say that in non-Winter the statement remains true. You'll be hard pressed to convince me otherwise on that one.
Also, I objectively rate cards by their effect on the game. There really is no preference in the way I construct decks unless two cards are of equal value. Two cards are almost never of equal value, either. It's usually very straightforward identifying which card is better. I do factor in synergies, though. That actually leans more on ktom's point that in some decks cards will be better than in other decks. For example, Steelshank's Reserves is an amazing card in my deck because I focus on high initiative plots. It's not a Bolton Deck either, but I'd be hard pressed to say it's not a high impact card in my deck. Right now this sort of deck construction, making uniquely suited cards better, I feel is rare. It happens with agendas because they're so in your face obvious.
You could convince me that this game is taking the standard competitive path. Copycat the best build while the truly top players are innovating. This results in a playing field that sees limited builts because no one really innovates. There remain cards that you borderline have to play, like Cavalry Flank, but I could get behind that line of thinking if some people put the effort in to make some very distinctly unique builds that were ultimately copetitive with top tier decks.
Going back to the agenda topic, though. They still are the easiest way to create diversity. I hate that fact, but what can be done to change it? That's the question we need an answer to.