If the current state of reactions reflects Larian's intentions, it is likely that Counterspell and Shield won't make it into the game, either. So that will effectively make those unstoppable.
Also, I forgot to +1 your original post, so +1.
Not including Counterspell and Shield will severely dumb down the game play for casters. I don't remember too many details from BG2, but I do vaguely recall fights against high level casters where I had to plan ahead and prepare spells that would peel off their layers of protective spells such as Shield and Stoneskin before the martials and wizards could commence with the killing.
