I've always thought of collective unconscious as one of those spells that's awesome in lore but difficult to translate into an in-game mechanic. It looks so cool when Y'Shtola darts in front of something, holds out her arms, and summons this impermeable bubble. But in-game it's kind of overpowered, unless you weaken it to the level of asylum or sacred soil, in which case it's not worth channeling, and the channeling is what made it cool in the first place.