I'm just going to leave my opinion on your thoughts, while I can see where you're coming from it's pretty unrealistic.
Any champion should be auto attacking in a fight, even mages, and if they aren't doing that than that's a mechanical error. If you haven't seen high level play of mid laners like ryze or syndra, they are often weaving in auto attacks in between casting abilities to maximize damage output over a time frame. There is no champion who isn't free from this fact, including any of the ones you listed. Putting it to proc on abilities would just lower the skill cap needed to maximize damage output, which wouldn't be fair to anybody who's actually practiced on maximizing dps.
I could possibly justify the range lockout, though I haven't messed with it too much so i'm not sure where that is.
Fleet footwork is a direct copy to warlords blood lust. It's supposed to be off auto attacks, same as before, for champions who build energized items. Putting it off on abilities would break energized items, and would completely defy the point of the keystone to begin with.
Arcane is based on if it's aoe, which jhins ult is. It's classified as aoe, because it is aoe, else they would change it to single target.
I'm open for discussion, but it seems these are all pretty sorted as to the direction riot wanted to take it, and they seem pretty well balanced mechanically.