Not sure if everyone is aware, but one of the reason all shields in the game are so powerful, is they can not be crit on. In last night's live stream, the devs confirmed that this will change.
It's something that should of happened from day one, but when this goes through there is something that needs to change. Currently shields have no mitigation at all, your resistances play no part in them. That needs to change, otherwise they will become the equivalent of having fresh air wrapped around you.