Destiny 2 looks amazing, straight up looks fantastic.
The biggest complaint and one that I can honestly understand, in regards to the negativity build up, is the state they've left D1.
The meta has drained the fun from the most hardcore of fans, it has sapped the originality out of plays and styles and left such a bitter taste, that when the idea of a sequel to this, arises, it brings out the current frustration.
Other metas were annoying, they made people change or adapt, yes people whinged but you could in a way play around them (you get stickied by a curve ball fusion, you're -blam!-ed, regardless) this meta I've seen the most cool headed player rage and several friends quit the game and cancel D2 order (though that may change closer to date)
This, I posted something to this effect a bit back that if they upset the fanbase enough it'd cause a number of folks to either hesitate, or not buy the sequel at all. Which is why they needed to be very transparent this time around, give the fans what they wanted, give them a ridiculous amount of choices to choose from. Supe up this hype train, and Bungie can do it, it's not a question of if, but their willingness.