Larian Studios Forums Divinity - Original Sin Divinity - Original Sin - General Glass Cannon Without Lone Wolf.

You should put Glass Cannon on every char regardless the difficulty setting.
You will have to invest heavily in CON (same level as SPD, 2 higher for LW chars), so you will still have more than enough HP.
Lets say you have a warrior with 9 AP, you use 2 AP to get next to an enemy and can use an ability (other than Flurry) or 2 1h attacks.
In the same scenario, a warrior with GC will still have enough AP after moving to cast Rage, Flurry and attack with a 2h weapon.