Some possible examples:
Armor:
Light Armor is in serious need of new materials. Dawnguard and Dragonborn helped out a bit, but so much more could be added.
Make chain mail a part of the Steel Tree
Make Mithril available as part of the Advanced Armor Tree
For nostalgia, bring back Morrowind style Glass Armor and Weapons as a Glass variant.
Heavy Armor - more closed helmet options. The Dawnguard closed helmet is the only cool looking one on the game (ebony and steel plate helms are terrible looking). More options here.
Weapons:
Spears - I don't care for them personally, but folks seem to want them.
For the Mages:
Wands: As opposed to staves which cast spells according to the enchantment and charges - wands could amplify existing spell types. For instance, a wand of fire would increase the power of all Destructions spells dealing fire damage. A wand of protection, when equipped, would increase the power of all Alteration spells dealing with personal protection (stoneflesh or whatever). If you did not have a spell of the right type, then the wand would be useless to you.
What would you want to see added to a Weapons and Armor Pack for Skyrim?