For charge effects, it looks like proper implementation is a long way off. Thinking aloud:
Mangos currently uses Relocate, so server-side travel is instant. Judging from videos, charge is not instant - in fact, speed appears to be constant and independent of distance. A special charge movement generator would be more appropriate.
The stun spell is triggered - if travel is not instant, the stun would happen too early. So the trigger spell effect should not be processed immediately, instead being handed off to the charge movement generator. When the destination is reached, the spell should be triggered.
If the charger gets stunned or something, the charge movement generator should be interrupted.
Also judging from videos, it appears that the destination is never updated during travel. We can do better though, just depends on how blizzlike people want it