Guild Wars 2 is such a radical departure from the first game. I understand the frustration of people who wanted more of the same as GW1, and instead, got something so different, there was little common ground.
It likely would have gone over much better had ArenaNet not called it Guild Wars 2. But it was their prerogative to do so.
It's hard to argue with the numbers though. It looks like in the end, ArenaNet made the right choice not to make a clone or direct continuation of Guild Wars 1. And in a sense, I prefer it this way too - GW1 and GW2 can be played separately, or together, and they don't compete. The first compliments the second (with the Hall of Monuments). And considering how many people I see running around with the maxed-out HoM titles in GW2, it's not been all doom and gloom for those coming from the first game.
Heck, Guild Wars 1 got a huge boost thanks to Guild Wars 2, people wanting to go see what the first game was all about, get some neat Hall of Monuments stuff. And GW1 is still 100% playable today, if a bit bloated from so much system creep over the last decade. Not much left for build diversity either in GW1, it's either Discordway or no way, especially if you want to get into parties doing the high-reward stuff. For all of its huge skill list, I'd wager 80% of them almost never get used except by people doing one-shot trick builds for PvP, or experimenting in PvE before just taking the 'best build' off the wiki and rotflstomping through the campaigns.
As for GW2, sure there's a lot of zerging (as there is in any open world MMO), and the "unity" system means you want to keep all the control systems in play (buff debuff), but I don't see either as problem. There's plenty of challenging content that cannot be zerged, and a person's skill is far more important than their gear or build, which was the point. Though that's not to everyone's taste.