Firstly, I agree that you shouldn't need to research D&D to be able to jump into BG3. And you currently don't. I didn't, and I've been playinn EA with only... 2 or 3 sessions of D&D under my belt.

Now onto the important part, I still firmly believe that what Larian is doing isn't "making multiclassing easier for newbies." Respeccing does that, and I'm fine with respeccing at least to level one. No, what Larian is doing seems very obvious to me as trying to make sure players do all sorts of crazy combinations of multi-class because that's their idea of fun. With the items they're throwing around and whatnot. Think about it, if you're new to the game and D&D, you're not going to find most of those items they're talking about sprinkling around. So if a newbie tries to multiclass, isn't it more likely they're going to walk into a bad build ratherthan less, in that case? I'd argue that the 13 attribute restriction is probably more a help than a hindrance, because it makes sure a newbie isn'g going into a multi-class woefully unprepared for what they need.