So my little thoughts about it. Developers made world and just decided to split it on 3 alliances but keep all territories available for other faction after reaching level 50. This enhance end-game largely since we have, to be honest, three times more quests, so firstly we leveling to max level, spending x hours, than made quests in next zone spending again x hours, and last zone again x hours. 3 in 1 of leveling quests. That means more gold, more useful things if there be any. I never understand people who make characters of another faction and start playing with them. In my opinion, if you find your main character boring, you made wrong choice at start. Wasting time on alt characters will make your main one weak and non competitive. So such zones for me is very good: I will increase my own wealth, exploring new territories. As for lore part, just one simple quest can repair all: make the character double/triple agent, that work on profit of all three alliances.