I'm quoting this from the 'Your Writing Process' thread over in the fanfic forum -
QUOTE(ghastley @ Feb 27 2015, 07:17 AM)
...
I'm now trying the same thing with Willatu, a Bosmer archer. She's doing Bound Bow, instead of Legendary Ebony Battle-axe, so she's more on the magical side, and Smithing doesn't help. That's hurting Derkeethus, as she can't improve his equipment the way Ina did Erik's. However, with Stealth perks adding to Archery and Conjuration for her bow, she's dishing a lot out at range, and not getting many close encounters where he's needed. She can also summon an atronach to supplement, or raise someone she's already killed.
So in each case an overpowering weapon trumps the need for armour. I can see that this could hit diminishing returns at high levels, as the weapon improvements will stop when Ina's smithing caps, or Willatu's Conjuration runs out of useful perks. Ina can switch to Alchemy to continue boosting her Smithing, but I'm not sure what Willatu can do.
,,,
I overlooked something that might help you. Enchanted 'fortify archer' items for the head, hands and ring slots. Buffy doesn't worry about this because, as I said, we just tweak her mystic bow damage to taste in the CS. If you're foregoing that though, such enchanted items, combined with trying to limit how high your character levels might help keep the mystic bow viable enough.