In fact there is already a mechanism in game to control boosting by regulating the amount of xp rewarded based on the group size and level composition. Boosting is in fact intended game play.
There are some arguments to make about using mob pathing to avoid melee combat, but kiting is also intended game play and was done to the extreme in Vanilla (Kazzak says hi!)
My interpretation of the comment, which is vague (the flip side of broad), is that they are targeting bots and gold sellers. Which are becoming an increasing problem.