I literally just mentioned this in a post I made 10 minutes ago before I seen this lol.
My suggestion is to give higher values to affix’s on certain armor types and add specific affixes to certain armor types
Cloth- can have higher % on all Focus affix’s, affix for rune damage, affix for additional intelligence or faith (example adds 3 to intelligence), higher percentage for speed affixes
Leather- can have higher % on all stamina affixes, damage for Stamina using attacks affix, affix for additional dex, higher percentage for speed affixs
Mesh- can have affix for additional strength and faith. Healing affects affixs, charged attacks affixs.
Plate- can have affix for additional strength, thorns damage affix, melee damage affix’s
Of course you can get any stat still on any armor the above listed per category will just be higher then That you can get on different categories
Edit: you might want to read rest of my post to understand why someone might want to use leather for more stamina.