I agree with Mirage and SE on this. There should be some incentive to run around people instead of 'through' them. This is a brilliant solution that does not completely remove collisions. The Mirage solution to slow down players is also nice, but this simple solution is sufficient for me. And 10 seconds is certainly a long enough time. People in your way while kiting creatures (like when we would kite creatures such as Jailer of Temperance) adds a nice strategic element to the battle when you have many people running around in circles.