One of the major themes here (with which I completely agree) is that one of the biggest whiffs (with sorcerer features and elsewhere in the game) is information availability & clarity. Unless we do the kind of structured testing you're doing, there's a lot of information we just have to figure out for ourselves, and hope we're understanding it right. It's an issue throughout what we've seen so far, and I hope someone at Larian has already gotten that message and is working on it. And this applies both to main UI and what's in the combat log.
One of the areas you didn't address was the non-combat aspects of the class, dialog options, interactions, etc., and I think they've done an excellent job in that department. My sorcerer playthroughs have been really satisfying in that regard.
"My magic could kill me at any moment, you think I'm scared of /you/?
Dialog/interaction-wise, sorcerer feels like there's been much more effort than the other classes.
But to one of your main points, 100% on the "as a player, this is confusing and ambiguous" situation.
