I'm someone who never actually played Destiny 1, but I was looking forward to Destiny 2.
I'm glad it's adding Raid matchmaking which was a one of the things that kept me away from D1. Another thing that kept me away from D1 was the lack of interesting story and/or single player content; all I heard about the game and saw from playthroughs was that so much of the structure was the basic go to area, push button, defend area against waves of enemies. This was something Bungie seemed to start doing more and more ever since Halo ODST (Halo Reach had it a LOT) and horde mode type stuff isn't my favorite thing (as its own mode sure, but not as a main portion of a single player).
Honestly, I just haven't seen enough of D2 to judge whether it's enough of an improvement that it'll get me to buy it. It doesn't sound like there's a lot of areas at launch (and the ones it does have didn't look or sound particularly interesting). The gameplay looked a little more action packed from the demo, but that was obviously a big opening setpiece, so I'll have to see if the rest of the game keeps up that quality.
So as someone who's only experience with Destiny 1 was videos online (Giant Bomb quicklooks and Raid playthroughs mainly), D2 really didn't look THAT different to me at its reveal, and a lot of the small (but meaningful I'm sure) tweaks don't mean a lot to me as a someone new to the series.
I guess I was expecting a more noticeable bump in quality like from Borderlands 1 to Borderlands 2; new classes (all except the soldier were new in B2), very obvious bump in graphics (not saying D2 looks bad, just not that big of a leap from what I've seen so far), immediately noticeable changes to the loot (haven't seen enough of D2 to know yet, but B2 added a full new Slag elemental type that changed the game quite a lot), new types of loot (again, maybe D2 will have this, but in B2 it added class mods as a new loot item which was a pretty meaningful type of loot).
Granted, I had played B1 before B2, so maybe the difference were more immediate to me because of that compared to D1 and D2. I'm still looking forward to seeing more of D2 and still might get it depending on what I see leading up to release and what the player/reviewer impressions are like. It helps it's on PC too, so it will at least look and play nice and smooth,