So I'm creating a rogue character and I'm going for max efficiency. This means maxing out armor rating in as few perks as possible, using all crafting skills, etc. So with maxed out magic resist/elemental and maxed armor rating, are health upgrades necessary or do I go completely stamina?

200/700/200

Use Absorb Stamina weapons.

all health, use vegetable soup.

I've got like 500 Health and 250 Stamina (maybe 350?) (210 Magicka I think) at 68. I have Legendary Forsworn Armor past the cap and kill everything easily. I use Legendary Ebony Daggers that do like 157 each, but I have all the 1-H perks that apply to daggers and Smithing perks up the Heavy side to Dragon.

I'm pretty far along with my thief character, and her build is about 80% Health and 20% magicka. Light Armor doesn't encumber you so heavily that fleeing devours your stamina, and even so, Sneak level so damn easily that you'd have to stand up and jump around in an enemy's face for them to notice you after a certain point. Something I do on all my characters is max out/get most of the perks in Enchanting because it's so overpowered and insanely useful. So if you think you got too little stamina or whatever, bam, enchant it.