What I was thinking was this, if all the items we could previously use straight from the inventory, such as potions, spell scrolls, soul gems, had to be equipped to a hand. Think about it, previously you are in a fight, you have your sword and shield out, things are getting tough, you can click on the inventory, take two healing potions, poison your weapon, recharge the enchantment on said weapon, click off inventory, hey presto, healed and recharged, no penalty, look mom no hands.
If instead we had to equip items such as potions, and suffer any penalties from sheathing equipment, even though it is only for the length of the quaffing animation, I believe a small detail like this could make combat that little bit more challenging and interesting. No more spamming that healing, and the chance to be unlucky and get killed while drinking a healing potion should keep you on your toes.
In fact you already have to do something like this in a way, whatever system they use. Just imagine your warrior has a fireball scroll, before you just assigned to the spell button, and cast when ready. Now you would have to equip the spell to a hand anyway to use it. I think, rather than have your warrior walking around with a spell ready, it would be nice to equip the scroll to a hand, maybe with a slight extra 'use' animation, on top of the one for casting, to simulate the time it would take to read.
Suggestions? Arguments? Show that you hate this idea? Feel free.