Actually the early districts are full of players, but nobody wants to group as it is easier and quicker to do it with henchmen in most cases, its not untill you get to Kryta that you find the amount of regions start to slow down alot and grouping gets trickier. I like the new system, maybe if they merged areas with less than 10 people into the international district would be the ideal solution.
Then if you cant get a group then its either that you have a bad rap or everyone has moved to the american servers.
That will be an issue in the long run, as more players emigrate to american servers as the want to try the high level maps that require favour of the gods.
Could end up with alot of players ending up on the american servers and very few on the european.
Going off topic, but they should open them maps reguardless and just have the favour of the gods increase PvE drops, i.e slightly better vs charr, and increase % drops of said upgrades, and / or increase gold drops and amount of cash merchants offer for goods as this wouldn't effect the PvP side of the game, but would help combat the migration of highend players to american servers.
The principle of GW would then be focused more on the actual guilds rather that the countries. The idea behind international guildwars is sound, but alas with language barriers and human nature it is not practical.