Half of a duel is how not to get hit. The point of ES is to take the bulk of the damage so you can survive with more hp. Sure FB and Lightning might take your mana down fast, but blizz and orb really are not a problem. They are based on lowering your resistance, not on pure damage.
I don't see how you get hit by more than one spam shot without regenerating mana, considering that spam is usually in random directions. And it's not like you'll survive a good namelock from an fb sorc either way. So the one situation in which you won't regenerate mana is when you're namelocked, in which case you'd be dead, ES or no ES.
I don't see how you get hit by more than one spam shot without regenerating mana, considering that spam is usually in random directions. And it's not like you'll survive a good namelock from an fb sorc either way. So the one situation in which you won't regenerate mana is when you're namelocked, in which case you'd be dead, ES or no ES.