1. you can unlock your hotbar, and expand them, and rearrange as you wish.
That's irrelevant. I'm talking about hotkeys. Four bars, defaulted to the standard 1-= and the subsequent ones with modifier keys and the hotkeys for bar 1, bar 2, bar 3, bar 4 customizeable in the options. Arranging them how you want is one thing. But hotkeys are extremely important for some classes like Sorceress & Wizard that have oodles of spells to manage.
3. O key can do some of this
It sadly cannot. It only provides an aerial view which cannot tilt to target or see things at awkward angles. Though it is a nice feature to exist to be sure.