If it is the designers intent to have some things that do require a tad more planning and foresight to achieve in the game then that is alright with me. It is no different than having to use a strategy guide to find all of the hidden X to unlock Y in a console game and such. However, it is the attitude of players I have seen all too often in WoW (and it seems some people will carry it over into GW2) that if you don't research how to play the game then you're terrible and should go die in a fire.
If the intent of GW2 is to have all aspects of the game require research outside of the game itself to be able to advance through the game in any way, shape or form then more power to the folks making the game (Though I would agree with the person who pointed out that that would be a ill-advised game model if you're required to do homework just to play a game) However, if only certain aspects of the game require this sort of commitment, saying everyone who doesn't put in the same amount of time outside of the game advancing their capabilities in the other areas of the game are being ridiculous.
I do hope that they realize that having just one difficulty level for a game that has no finite end (IE single player campaign) is a bad idea in this day and age as it extremely restricts the appeal of your game to a niche audience. If that is your intention, whatever works for you. However, I don't get the impression that with the amount of effort being put into GW2 that they only want it to appeal to a small group of people.