Aside from the paralyze spell and, of course, the oh so awesome Mass Paralysis, the alteration tree is completely pointless with every thing else it offers compensated by armor and shouts (even a pure Mage should use regular armor for my armor than offered in alteration and since you can easily create all the enchantments you need).

But now Dragonhide has stunned me. Most of is the max armor cap for damage resistance is set at 567 with 80% damage resistance then. I assumed Dragonhide doesn't stack that at all making it useless too. I was wrong. And what better enemy to test its use against than the fearsome EBONY WARRIOR on LEGENDARY difficulty?

For all you noobs, the EW added by dragonborn DLC is arguably the hardest boss in the game (some would say Karstagg is but I disagree). Miraak and Alduin are certainly crap compared to him.

And at LVL 81 with 550 health and max armor rating on legendary difficulty, the EW can one shot me with his bow. That's right I die in one hit from that bow. His sword with a power swing rips close to a 1/3 of my health with regular swings taking decent size chunks out. So he can kill me pretty quickly if I'm careless and if he Fus Ro Dahs me to the ground and I have no distractions to take his aggression away like conjurations then I'm usually dead as his sword swinging at me quickly kills me before I have a chance to get up.

So I tested him starting the battle with my same armor on but this time I casted Dragonhide. Suddenly and miraculously he was doing nothing. Well of course that's an exaggeration he was still killing me fairly quickly but not in any life or death situation where I had to keep paying attention and cast grand healing every 3 seconds. Suddenly his power swings were only doing decent chunks rather than a third of all my health, his regular swings did almost nothing, and I could survive his bow! Of course he was still far more deadly with his bow (if the EW fought with his bow as a primary instead of his sword and shield, he would be MUCH harder) doing 161 damage to my health. But if you do math I could suddenly take FOUR hits from his bow with full health and max armor rather than ONE!

And on top of this Dragonhide actually is affected by the duel cast perk so you can actually make it last a decent time of 100 seconds if you use both hands. It' would still be useless in my view if you couldn't make it last longer since 45 seconds goes by way to fast where you only have a chance to cast a few spells before you already need to cast it again.

So yes perhaps alteration can be very useful for those of us who only fight on legendary difficulty. It truly does stack an additional 80% damage resistance to your max armor with 80% damage resistance making you take just a fraction of the full damage by opponents when your armor and Dragonhide are combined.