Lets not kid ourselves here, adding good 0 slot weapons did not really change kiting ranged. The only thing it did was make them much more deadly when cornered. There are a few ways to nerf xbows that would work nicely:
Nerfs that must happen: Reduce missile speed. I have been shield pierced through a heavy round shield way too many times. It is laughable actually.
Other nerfs:
-Raise arbalest strength requirement to 18. It would not break the class, but it would be a pretty strong nerf.
-Add some form of PD for xbow only.
-Ranged limit per map.
-Raise to 3 slots, effectively limiting xbows to ONLY 0 slot weapons.
-Modify the effective WPF equation for ranged only. This, if possible, could be in effect when a character possess over X wpf in a ranged category. This would force all ranged into lighter armor to be effective at their class, making them easier to kill.