So, so far the factions you join in your personal story feel more like a stepping stone or plot device for the story as a whole. I would LOVE to see that changed in a way that would make them a proper faction you could work your way up in, and maybe gain access to higher tier karma vendors within your chosen order!
There’s a few quests with your chosen factions at the moment, but they’re very limited and you advance through the ranks far too quickly. Having some optional side quests that would help you build renown with your order would be great, and a fun game-play mechanic all on it’s own.
I’d hate to use WoW as an example, but I seem to remember it had factions too, and that you would build reputation with them by wearing their tabard in a heroic dungeon, something similar in GW2 would be great! Since having side quests account for all of your reputation gains would be a little difficult.