OK, I'm not sure why we're comparing a PURE mage with an Enchanting warrior. Sure, the warrior Can find enchanted gear, or even take up Enchanting, but in that case, there's no reason a Mage can't use Armor, or a better weapon than a dagger, for instance.
2 Stop Dual Casting as the only attack. If you shoot 1 Incinerate, then another while they're on fire, the 15 ectra damage you get out of Dual Casting is made up for by the On Fire status effect. Use Dual Casting ONLY for impact, your Magicka will last longer, and so will you.
There's Magicka reduction in the game, it goes up with level, so that when you do get up to Incinerate, you should have the Robes, and [ossibly a Circlet to cast them. The operative word is REDUCTION. For total elimination, you either have to Enchant your own, or exploit Radient for Peerless Gear. What this suggests to me is that Magicka Elimination is a late game thing. Untill you get it, how do you even survive to that point without understanding the Basics of Magicka Management? You can do it with Stealth, presumably you can watch your Health Bar before it gets down to 0, so what's the problem?
I know, Desrruction doesn't do enough damage. This makes it more difficult. Why are you playing on Master in the first place if you didn't want it to be difficulty? To prove what a badass you are? I regret to inform you that Destruction is not the way to go to be a badass. You're least effective up close where the badasses are, you actually have a Damage Cap, and you can't swing indefinitely. OTOH, if you wanted to be a badass Player, instead of having a character that does it all for you, then yoou'd go ahead and learn how to use Destruction as is. All I hear is a bunch of whining that it's not powerful enough.
Badasses don't whine.