The personal stories should have just been that, personal.
IMO the whole campaign on Zhaitan should have been just that, a campaign.
The entire thing is instanced anyway, you can have your living world, your moving calendar, all that stuff and just leave these major stories (like forming the pact to defeat Zhaitan) as campaign type chains. Then you have the personal story be a self contained story to your own experiences. They did fine for the first 20 or so levels of personal story but from there things start getting less and less personal culminating with Traehearne.
THIS is imo the main issue with the PVE part of the game as it currently is. “Why?” one might ask. Well from a design point of view the current system creates several obstacles hindering both character development and addition of new content, yet at the same time when altered somewhat it has incredible potential.
Because like Lostwingman already stated no matter how you start out (class, race, etc) eventually you always reach the same conclusion in your personal story and therefore it ceases being a personal story. This also becomes a problem when new content related to the ps is added, as it HAS to pick up where the player left off, which in the current case is exactly the same for every player.
One of nicer features of GW1 were the missions. Although at first glance they appear similar to the personal story instances of GW2 they were quite different. They provided a challenging and a mostly immersive experience that promoted group play, while maintaining a linear, easy-to-follow, yet flexible framework for the narrative of the game. Although I’ve seen Anet being criticized for their inability to properly convey a story imo the missions in GW1 did so quite adequately. This was mostly due to players being able to connect the dots between the events in each mission (aside from numerous sidequests).
If you follow the campaign idea and seperate the personal story and the main(retail) story/campaign of guild wars 2 you get a similar and very flexible system in return, potentially resulting in multiple campaigns running at the same time, some depending on the completion of others, while getting as a bonus on top of that a basically neverending personal story in which some of the elements that currently needed to be put into the living story could be incorporated.