Put items on the GCD -- PLEASE!!!

[Ephany]

As a MRD I have 2 items in my hotbar - hi-potion (could save you long enough to get that vital cure) and an ether (bit odd I know but sometimes that extra flash comes in handy when things are asleep).

I honestly can't think of any other items you'd need in your hotbar.

Food lasts 30m and Esuna should take away anything that's crippling your character.

Just get a decent party / use some strategy instead of relying on items.

Pretty much this.
Anything other than those two items can just be selected before hand in any situation.
These are the only ones you would need in a battle.