Yea, Rift is probably the best example of terrible MMO questing. Potatoes makes a note to tie back his argument to the new living story thing in GW2. Which I also agree with as a possible avenue to add more personality and player investment to the game's world.
Things like this: http://wiki.guildwars.com/wiki/The_Villainy_of_Galrath
Stand out to me in Gw1. Or even like the bonuses such as saving the piggy in that one early mission. Or the way Cynn and Mhenlo have their stories revealed over time. I suppose a lot of the backdrop of the Order of Whispers, Sunspears and Houses of Luxon and Kurzick-- so much great world detail.