Bolt escape is a perfectly fine idea in a rock/paper/scissors game. I think the imbalance arises because it uses a resource pool that sorcerers tend to stack anyway, leaving their stamina pool full for other CC breaks. Let's face it: bolt escape and its morphs are really very powerful CC breaks - you can't even hold someone with a root when they decide to port. A simple fix would be for Bolt Escape to continue to cost the same amount of magicka, but require a substantial amount of stamina concurrently. This can easily be explained lore-wise: teleporting yourself is a physically taxing spell.