I would say no. The lack of Npcs had no effect on XI with server population.

3 Things will populate the servers

1) Content
2) Making worthwhile content outside Uldah (put all the best leves in 1 zone and it is obvious why the whole server is there)
3) More People... MMO sub count attracts more mmo players one of the reason WoW got so huge, person looking for a new mmo and sees 1 at 550k and 1 at 6million which one are they more likely to try, especially if it is their first mmo.

SE's issue are point 1 and 3 more then anything. They need content to hold the sub count and get fans back, but unless they can attract a respectable subcount players will not be willing to invest time in the game.