Market wards will suck unless they are completly redone, but they are not game breaking.

In my eye 4 things are threatening to kill off 2.0.

1) Regional Servers if the population in all regions is not large enough to support a game where it only functions 8 hrs a day. IF there is only 1000ppl online a day... the server economy will crash and the game will more or less die out quickly even if it is strong in other areas... see Aion.
2) Population boom and drop. It will happen. SE needs to immediately server merge once the new game noobs leave. (too many mmos wait too long to merge servers.)
3) Lack of Endgame
4) Extreme casualness. What is killing WoW off. Listening to the playerbase is good caving into them is the worst thing ever. The customer very seldom is 100% right, honestly I will go as far as saying the customer is never right. Company need to listen but not blatantly do what the masses demand or you get clones and dull/insta-win/no innovation content.