The BG games had a very painterly style to the areas. Even though crude by current standards, they really were gorgeous. I'm not sure how that would sort of feeling would be imparted with today's graphics. But I think done extremely well, I might prefer something like that to striving for realism.
The BG1 and 2 soundtracks were also first rate. That music got etched into my imagination.
And the combination of great NPCs that were so perfectly cast by their voice actors was about as good as you could ever hope for.
Finally I want the same (or greater) loving attention to detail for the lore of the setting that the BG1 and 2 had.
I'm aware that combat is probably going to feel a bit different perhaps, because of 5E. But combat in the Infinity Engine was genius. This is a very high bar. Please don't screw the pooch on this.