i play on eu from asia and yes there are similar problems here. i'm putting part of the blame with my isp though.
add - /clientport 443 /mapLoadinfo - to your gw2 shortcut. take in-game screenshots whenever the map loads and use winmtr or similar to see where the problem with your connection to the server might be. if you use arcdps make sure to have "metric" ticked and see how often you get non-white R values.