What I'm more curious to hear about, actually, is how you arrived at the '85% 5e' figure.
Legitimately, I'd like to know how you got to that number - what you weighted in as accurate and faithful and what you looked at as not so, to deliver this percentage?.
This is an interesting question. How do you rank "how 5e" something is? Unfortunately, I don't think it has an answer - or more accurately everyone's answer will be different.
I don't think you can just go through every single rule, counting up the % of ones that are implemented correctly in BG3. Besides being incredibly tedious, some rules are obviously more important than others (e.g., the D20, actions during combat, the 6 main stats, spell slots) and should be given more weight.
Also, do you only count rules that are unique to D&D 5e? Other systems are d20+modifier based, and Pathfinder in particular has a lot of common rules...
