And I discovered the shield line of spells are practically worthless.
As a mage I have cranked the most of ny level ups into magicka. My stats: Level 46 Magicka(in gear) Health 180, Stamina 120.
Now, I haven't purchased mage armor perk yet, but with stoneflesh, my AC is actually 10 points higher in my current gear than if I had the first level of this perk.
So, the first level of that perk = worthless, and I'm not even in dragon armor, robes, mask, and dark brotherhood boots, and gauntlets, 130 AC. My AC would be 120 if just clothes and level 1 of perk.
Being destruction mage vast majority of my perks purchases went there, along with enchanting, smithing, alchemy, and alteration was my second school of perks. So, I tested damage.
With Stoneshield active, same npc, I took 110 points of damage, one arrow. With stoneshield off, I took 121 points of damage. Yep, stoneshield saved me from a whopping 11 points of damage. The weapon? An imperial bow. Yes, Ebony bows one shot kill me.
So, what is the point of mages and no armor? They would have to take the mage armor perks.
Oh and the last elemental destruction perks are worthless. Almost dead and I get a nifty effect? Really?