you can 5 foot step into and out of a threatened square with out provoking AoO in 3.5 as for running away you can declare a full withdraw, or a partial withdraw to leave a the threaten area to get twice you movement speed away (or just your normal movement with partial).
@ Eric
For laying down and mounting a horse. Lay down, then stand up. Obvious.
Mounting a horse, I don't know about you but I can figure out a way to jump on a horse without having to give it full attention
Same with opening and closing a door, easy to do with one hang or not giving it much attention, while picking up an item kinda acquire you to look at it alittle longer and pick it up.
Escapinga grapple: Your either being held by the one who would get the AoO or the struggle between you and the one holding you would make it really hard to take a clear hit on you and not their buddy
5 foot steps
a 5 foot step is something easy to do (maybe not irl.. but everything is 5 foot increments in DnD) its a simple step
if your limited to a 5 foot movement, you gotta struggle to take that 5 feet their for it no longer the simple movement.
for something more real terms to explain it: Take a step, easy to do. Then go take a step in knee deep mud, you hadda struggle with it more then simpley stepping
Now unarmed strike: It allows you to make a melee attack without Provoking an AoO, and get them verses someone who attacks you unarmed with out it. Meaning you know how to fight with your fists, your not some random punk who thinks he can fight with them any more. It doesn't help with grappling because that is not striking :3 that is grappling. Thus improved grapple means your trained to grapple
