Why do high-agi melee char with a great long bardiche can hit&run (which is basically kiting) and archer shouldn't be able to do that?
Because they are not comparable examples.
Regardless of how much agility he has, the guy with the Great Long Bardiche or other long four directional weapon still needs to step within retaliation range of his opponent to actually do damage. Said opponent will be able to block, counterattack, and potentially defeat him as a result. An 18/24 archer, on the other hand, does not need to step within retaliation range of his opponent to do damage. If he is playing correctly, the archer will be able to run away from his opponent almost indefinitely and deal damage in such a way that his opponent has no chance of counterattacking--ever--unless it's a thrower.
Even still, this might be a somewhat acceptable situation if this 18/24 archer, the one that is effectively invulnerable against the majority of melee players in 1v1, wasn't also the most accurate and damaging kind of archer as well. As many, many people have previously pointed out, a 30 str 10pd archer only does a little more damage than a 18/24 archer at distances closer than 20m and actually does less damage than an 18/24 archer at distances further than 20m due to much higher wpf. The 18/24 archer has fantastic draw speed and accuracy compared to the 30 str 10 pd archer for the same reason. How is this in any way balanced?