The concept of guildwars was really good, but the fact is the execution was horrible. The only thing that kept me playing was PVP and because that became buildwars i quit. The truth is A net made some bad decisions ingame, eg. making henchies a viable option, then making heroes, because they destroyed the whole idea of a massively multiplayer game. However GW was probably doomed from the off due to the fact that every map was instanced.
Anet have got some serious work to do if they want people to play Guildwars 2.