I agree with Nigeyy.

i. & ii. would be nice using the same sort of locking straps as toe clips used to use.
iii. is always a problem with those of us with, uh, proper sized feet.
iv. You can never have too many separate pockets unless they aren't waterproof.
v. My old Nashbar bags are like this and it is handy though the mechanism - snaps - sucks since they're hard to engage and disengage too easily.
vi. I don't need a backpack. I NEVER need a backpack. Even LOOKING like a backpack would piss me off.
vii. The major problem I've had with panniers is that they sag on the ends and start dragging in the spokes.
viii. Size is a real peoblem. Everyone wants to carry everything but the fact is that experienced long term tourists usually take less than weekenders. This implies that moderate size is better than large unless you're carrying food and water into desolate regions.