Agree with all of this, dunno why they've made sneak attack into some weird special action you have to take. As much as I love the progress Larian is making, it seems all too apparent that they either didn't actually want to make a proper D&D 5E game, or just weren't up to the task of it by the time EA rolled around. Lots of very basic D&D rules missing or implemented weirdly, didn't really help that Solasta came into EA around the same time and was much more consistent and true to the 5E rules.
Hopefully, Larian listens and implements things properly soon which they certainly seem to be working on at least, which is certainly a positive thing, just weird that they left some things out and then what they did put in was just flat out done wrong.