The initial story of GW1 had a lot of the same problems as GW2. Prophecies and GW2 both continually start stories without truly finishing them, so you don't heavily invest into any plotline too much. By the time you're at the end of Prophecies killing the zombie version of fallen hero, you barely remember the long strange trip that got you there.
Gw2 has the same problem. You go through three or four different changes in story arc and focus, barely investing into each part. I thought they had fixed this problem with both Factions and Nightfall (which has one of the best MMO stories), but they returned to the same problem. From what I've heard, only the first 30 levels of story were mostly done in-house and the rest they had to go outside of the company a bit to finish the game in time. That doesn't excuse Scarlet though.