Sort and simple answer is yes! My second character is based around this build. I am currently level 32 and I am quite enjoying it. I rarely use equilibrium as I rarely run out of magicka and when I do I have a loooot of potions from hoarding them around.
At the moment I am dual casting apprentice level destruction - and yes this more than enough to kill frost dragons. maybe it takes a few more hits but it staggers dragons (not Alduin) and I am waiting till my enchanting is 100 so I can make my destruction free and not waste anymore perks. I use rune spells and conjuration (fire, storm and dremora lord) regularly to give me a tactical advantage.
Early game I'd suggest having a follower but not really that necessary later on.
I used restoration perks to increase my magicka regen by 50% so I can use atronach stone.
i use arch mage's robe, morokai's mask and self enchanted amulet and ring for giving more magicka+magicka regen. So I suggest doing college of winterhold quests asap. Right now I have around 430 magicka and 410 health.
Hope this answers your question though I am a month late :p
Edit:
I will put up my character build here and edit it every so often if it helps:
- level: 35 (atronach stone)
- Enchanting - lvl 100 (and I always use grand souls for enchanting my
gear)
- Destruction - lvl 90
- conjuration ~ lvl 86
- alteration - lvl 33 (I am including this as this is the next skill I
will try to develop)
- gear: orcish armor (destruction+alteration), ebony helmet
(destruction+alteration), ring (destruction+conjuration), amulet
(destruction+conjuration), ebony gauntlets (magicka+something nice). So
this makes all my destruction cost 0 magicka.
I tested this at the last part of the main quest-line
from the point where you enter Skuldafn.
It works rather well, would work better with some (crowd) control spells eg. paralysis from alteration, or some illusion spells etc.
Edit: various rebalances in patches since the below was posted (such as a particular spell's damage per cast) has made it inaccurate. I am afraid, therefore, that it seems that the author of the spreadsheet has taken down the link.
A Solution
I developed a basic spreadsheet that allows you to find out all the above questions, and more. V1 provides a full workup of magicka and all related enchanting effects, and provides detailed damage info for destruction spells.
A better VBA model I was 30% through is on hold while I enjoy a DLC to my favourite game :D
An basic example with my current mage: Magistra Circe
Mirror 1: SkyrimNexus
EDIT: the sheet is locked to prevent accidental deletion of a formula. You can unlock it (no password) under the "Review" Tab (in Excel).
Best Answer
I used them for the lols during fort attacks in the Stormcloak/Imperial war quests, since there are a lot of targets around you. You can also sneak up to groups of enemies while stealthy/Invisible and let off one of them to start the fight.
Other than that, I didn't use them much, for the reasons you mentioned. Of all the perks they put in the game, I don't know why there isn't a perk to make winding up Master spells faster. You're really vulnerable while preparing and holding them, since you can't move.