I was worried about that because I'm a returning player after a 5 year break. But I've found a very active WvW (my primary focus), and open world PvE maps are still populated, always helpful people around. Got my griffon unlocked within about a couple weeks after coming back to the game. Haven't tried raids/fractals yet which I want to eventually get back into, but I know some guildies who play them still. Just join a guild, have fun.