What's so good about Guild Wars 2?

On my other thread here: Anyone over 30 feeling that it's hard to find an MMORPG that they like? : the community recommended some mmorpg games but Guild wars 2 stood out for sure, it got an overwhelming amount of positive responses along with wow: sod and perhaps bdo but I understand the last two better, it's not hard to figure out what the community likes on them, also they are not coming even close to the positive responses of GW2.

Guild wars 2 was one of the mmo that I didn't play a lot, I didn't play up to max level because I was burned out on questing and I didn't want to repeat it, I played on release back on 2012 and mostly did some pvp, I gave up on the same year, both this game and diablo 3 released on the same year and I didn't like any of them so I went back to wow in order to play pandaria which was an "ok" expansion, compared to what we have now.

Back then Guild Wars 2 gave me the same impression as any other mmo, that it's a bad copy of wow and that it will fail the same as many other mmorpg that tried to compete with wow. I can see now that it's very popular and not far from surpassing wow or ffxiv, it's certainly on the top 3 spots.

I honestly don't understand why, it was very generic so I don't know what makes it different than wow or a game like eso. I played a lot of eso up to 400 CP, the monetization system was fair and you never fell behind since there wasn't gear progressing but there wasn't any activity that I would enjoy on this game, dungeons were boring (still much better than modern wow), campaign was boring, sieges were zergfests where you either killed them quickly or died quickly. It was very generic. There were other "wow" competitors that had some unique elements that I liked, eg. Swtor campaign but gw2 was very generic.

So what do you like so much about GW2?