There's plenty of things to fix, unfortunately. I'm OK with some of the bugs, mostly smaller things like not working item enchants, bugs in items description, typos and localization bugs, or even occasional crashes. But it's hard to accept bugged quest, issues with story integrity or problems in ending slides. Just from my first playthrough - 5 bugged quests, two of them making impossible to make alliance with two different factions (so you could say it's on a "game breaking" side of things), describing past events as something that hasn't happened yet to at least couple of NPCs (we're talking about main story here), and in ending slides I read about "cordial" farewell with one of companions which was anything but cordial. Things like these are breaking immersion heavily, to a point they can invalidate your entire playthrough and all decisions you made during the game. Not cool.
Does it make PoE 2 worse game than the first one? Not for me, as I see improvements in many areas in comparison to PoE 1, but I plan to complete the game multiple times anyway, and I expect several patches to be released, fixing both bugs and game balance. So I can wait, and I'm sure at some point Deadfire will really shine. But plenty of people will give up on game after few hours and will never give it another chance. And that's something that could be avoided.