I'm interested in knowing what your issues with it are. As someone who never played the first, I found it a pretty incredible and innovative RPG. Probably the biggest disappointment is just that I wish there were more monsters to fight, which I understand was a criticism of the first game until it's Dark Arisen expansion.
I'm really speaking for myself here, but my main issues were the micro transactions that are in the game. Before the game was released, it was announced that you can use real money to purchase wakestones to revive yourself, rift crystals to hire stronger pawns, a portcrystal to fast travel, and even to change your character's appearance (as well as some other items). After the game's release people quickly realized that buying these were not necessary at all and they could all be obtained easily through normal play, but the damage was already done. It left a sour taste in my mouth and made it seem like the devs or the publisher were not confident in the game and felt like they needed to add a way to milk some more cash out of the people who bought it.
As someone else mentioned, the microtransactions existing put it in a bad light to start
My main issue however is just how UTTERLY UNPLAYABLE it was for most people's systems on launch. The number of crashes and performance issues rivaled that of even Cyberpunk, and I still regularly play Cyberpunk. it was a complete and total disaster for many many people, and while it's likely fixed by now it was such a struggle and headache to get through that I'll likely never finish it.
I've personally got a lot of issues with it. It feels like the first game stripped of a ton of charm. The story has so many plot lines that feel pointless. The post game gameplay loop is, imo, inferior to the first game's. Not to mention the lack of variety in not just monsters but gear.
My biggest gripe though was how it just sorta ended. I didn't even know I was heading into the final boss fight when I got there. It felt like it was meant to be more of a mid game climax but, nope, here's the final boss.
A lot of my complaints can extend to DD1 as well but the charm of the game helped me get over all of its faults. Handing me essentially the same game with little improvements (and new faults, I'm looking at you dragon plague) was not the move.