I honestly have no idea what the BG3 devs could have possibly been referring to when they said they made changes to core systems that didn't translate well to video games.
There was dialogue from Swen before the launch of EA last year saying that they had to find a way to nerf Guiding Bolt because it was too powerful. I should have known then...
I think what it really comes down to, is that no one at Larian really grasps 5e beyond the most basic level of understanding. They really should have brought someone over from Wizards full time, to guide them through understanding the rules before they set out "adapting" them.
Probably could have gotten Joe Manganiello to explain it to them for free.
