I have a spell blade character that is about level 30 and still no challenge on expert. But one of the things I always use is stone flesh before I enter a battle. While I also use heavy armor and a one hand sword, I'm finding destruction spells surprisingly not that dangerous against most opponents. Still I'm trying to use it for range rather than switch to bow and back. The great thing about alteration is the added benefit of defense, but it also has a perk for magic resistance. I remember seeing a thread about how to fight against mages and I'm finding the flesh spell along with this added magic resistance is making me more buff against magical attacks. What else is nice is alteration raises surprisingly fast if you use a flesh spell every time you enter combat. If your having trouble against mages you should consider using alteration spells at least up to stone flesh and a few perks in magic resistance. Hope this helps.

Yeah it is pretty valuable to anyone, simply for the magicka mitigation.

For atronach perhaps, but I'm much happier with a 25% magic resist as one of two effects on my enchanted ring (with no cheap tricks), then spending 3 perk points for 30%. Neither am I interested in stoneflesh while wearing armor, the extra 7.2% damage resistance seems too weak to me. To each their own.

Yes but I haven't reached iron flesh or ebony flesh at expert yet. IDK improving the armor 100 points for 60s sounds good to me. Mass paralysis sounds interesting. all targets fall for 15 seconds. Besides I just go with steed since I like to sell more items. I go with magicka regen, magicka fortify, and one hand enchants. Blessing of kynarath for stamina and gaulder amulet, but need to get the complete version since now its only magicka. My magicka regen is so high that I never need potions. Still haven't found fortify heavy armor. And magic resist isn't that great considering the specific resistances are much better. right now its something like 210/280/210