Just wondering but why are people complaining about all of this aoe spell "nerfage" and then bringing up epics as a place where you "needed" crit firewalls???
When I run epics we utlize crowd control so much more than firewall it's ridiculous. Mass Hold Monster, Flesh to Stone (casters/rogue mobs), and some irresistable dance. The melees destroy everything and I go on my merry way to the next batch of victims. Boss mobs?? Just dps em already. If your melees don't have the dps to drop the boss, then your group wasn't ready for the quest anyways.
As for mana efficiency, use a Dreamspitter and mass hold/fts and that argument goes out the window.
Your example:
10 mobs + Max/Emp/Quicken/Extended Firewall (85sps) and mobs dead eventually
My example:
10 mobs + 1 mass hold =Dead mobs (0 kiting)
Now, if you're talking about soloing, then 1 symbol of persuasion (mobs kill each other).
I've been running my caster for a long time now and I don't see where spamming firewalls down until you see big numbers is mana efficient in any way, shape, or form...perhaps you gentlemen could enlighten me??