Yes I agree, so there is the potential for someone to make a really good D&D 5e RPG. The question is whether Larian's BG3 will be such a game, and that's where I have serious questions and a high level of skepticism.
Soon as that gameplay vid drops, we will have our answer.
To be honest, I'm not sure "soon" is listed as an entry in Larian's dictionary. I guess Descent into Avernus and the miniatures are part of the overall marketing effort but I feel that many fans of the series are not necessarily avid DnD players but primarily interested in the legacy of the Bhaalspawn saga and the Infinity Engine games. Perhaps the trailer was released too soon as I've thought of the post-announcement period mostly in terms of a dry spell since then.