I stand with penfold on this one.
Forget this Core + cycles thing - its a hold over from CCG and limiting available cards. I never liked this mindset then, and I don't now. The more cards the merrier and the more I can play the better.
If problem combos aride - the strategic banning method is the way to go. Identify the culprit and send him to the Wall. Even with all the legal cards, there are whole chunks that never see play (Rookeries, those kneel an icon events).
I wnat the option to go back and play as wide a variety as possible and teh targeted banning route offers the deepest pool and the most choices. It solves all the problems that have been voiced while elaving the player's with the most choice.