The moding community's dedication to the 5e rule set clearly shows that this community was far bigger than one would imagine. The system works if you stick to it.
I am very satisfied that mods check the 5e box very well...for the most part. BG1 and 2 were in the 3.5 era, and they were expected to be faithful to that system (which they were).
Showing my age a bit here but bg1 and 2 were based off 2nd edition ad&d ( i grew up playing 1E and 2nd)
NWN 1 and 2 were based off 3.5 perhaps you were thinking of those games.