Um... hope this wasn't suggested before, but the search option is kinda um.... not working properly. With google I've found everything but this.
My idea would be to get the one-time quests sorted and would only affect the PvE part of the game of course. In most RPGs when you check your log, journal, diary etc... you can see the quests you have completed. In GW you can see this as well but only until you get your well-earned reward. Why not make a Completed quests list with a counter (e.g. 29/54 -> 29 out of 54 quests done). Simply by putting a button in the Log menu. As you might have already found out I'm more of a PvE player who likes to do all the quests and missions + bonus (just like the title shows it for this one, though I still don't know what's the 25th mission, cuz I've counted 24). Still, I can't keep every quest I've done in mind (could have made a log about it right here at home, but too late to think about that by now). In case of the missions you can see what you have done and haven't done. Why not have the same options for quests? Even a new title could be made of this, like Tyrian quest hunter (though it sounds weird) or Mercenary of Tyria or something similar. Same goes for Cantha. Though only one-time quests should be counted (even the ones that require you to change professions) in the log, so no repeatable quests (like in UW, FoW and SF) or tutorial quests.
Suggestion: one-time quests sorted for PvE players
ReaverGTX