I'd start by making those items that are never used, better for a start. Who gets the 10% XP favor for example? No one. So you could boots it too 15% or 20%. You could give some life like +200, to claim some BoTF users. Health items are so strong and scale so well because of the available MaxHelath effects such as Sigil and Priest. There should be more effects that give +x% damage. Mana Steal/Reduce should be available. Reflect and Shield are cool mods too.
We could make mid cost consumables with OSkills, like a 3s consumable shield, among others.
Just some ideas.