Heart of Thorns was a real game changer with the introduction of gliders and the new maps were some of the best in the game. I haven't played in months but was thinking about firing it back up to see what I missed.
There is a diminishing userbase and this becomes quite evident on massive maps where you very rarely encounter another player. People have determined how to get to certain world events on a timer and they simply do trains for that in the hopes of getting better loot. The LFG is also so effective that people don't even camp locations for this anymore either.
I think that GW2 would have been a lot better if there were class specific abilities (the trifecta). There are a ton of options for stats for your character, but none of them seem to be terribly effective except for the ones that the community has determined to be the best ones. For one thing I like the idea of being a support class with a ton of ability to heal others and also take damage myself by speccing in Toughness and Healing, but it really doesn't seem to matter how much you up these stats, the difference it makes is negligible because the power means solo batttles last long (zero sum result) and heals in a team dont generally impact the rest of the group since most heals are not shared.
They can't change this now, the game is too old and the community would cry foul if they tried.
GW2 has already survived a lot longer than most MMO's but i suspect that their days are numbered as most people simply log in for the daily rewards, complete a few items to get the daily bonus, then log out for the day.
It is still a wonderfully designed game, but the players have figured out how to "cheat the system" using massive groups and unfortunately no one really simply explores anymore. I suppose this was going to happen eventually no matter what they tried to do.