Effects of speed on AC vs ranged

[CountofUndolpho]

The only rule I can find that seems to address this is the bit about losing your Dex bonus to AC when running.
As far as melee attacks go that's fine, you're easier to hit but with ranged attacks?

[Kayerloth]

While I see your point (a moving object is harder to hit than a motionless one) I think the assumption is when you are Running you are moving in a fairly predictable path and normally in combat you are still a moving target even if you are "motionless" on the archers turn but generally in a much less predictable manner. If you aren't a moving target then you are likely considered flat footed or surprised or some other condition which will provide to hit bonus and make you easier to hit than someone in combat. That make it make sense any better?

[CountofUndolpho]

If you are in combat then a ranged attack against you is at -4 unless the firer has precise shot to take into account the movement.
I must admit I was thinking of a mounted target if you are riding a horse full tilt you can go up to 250' in a round but you are easier to hit? Admittedly you have to run in a straight line but .....