i think biggest reason some people dont like the idea of buying cards is it makes the time they put into the game less meaningful...
ie. 1000+ games and endless challenges for a few measly cards that you are so very happy to get. And then all those hours of game time is reduced to some punk buying all the cards, you worked so hard to get, for $5. lol
cope2.... then what runescape is doing is working. some ppl pay, some dont. the ones that dont know they could and get a "better" game experience... some will ultimately decide to fork out money. Things go as planned for the people running the game.
If Kongregate gets it right, it can be successful with getting new ppl to buy cards. if not, then itll die.
the card winning rate is a bit of a problem i think... it shouldnt be by luck. because actually buying one becomes less appealing. but if card earning was a long grind (i.e. your first one at 50wins, then 100, 250...or whatever). then maybe people would rather buy.