I don't think that my judgement is clouded by nostalgia here. BG2 was pretty decent Day1. The Witcher 3 which also is a complex game barely had any issues at launch. Planescape: Torment was okay at Day1 while its newest incarnation also was a buggy mess at launch. I stopped that game because of that.
Minor glitches i get. They tend to get overlooked and at least stop you the moment they occur, not hours and hours later. I wouldn't have an issue here if my complaint was flickering textures or cut off animations, everything technical i don't care about. But something as crucial as the actual questsystem which is the heart and soul of every RPG? This is where i get out of dodge.
If THAT is bugged and not repairable with the first hotfix, then you fucked up big time. Thats where a dev should go:"Ah shit, sorry guys, but we have to delay the release due to..." - whatever. If marketing prevents a dev from saying that they need to postpone due to bugs, then fucking lie like every PR-Team does - "server crashed and stuff got lost" or "Belgium just got eradicated by genitalia eating bobcats". I don't care...