Ok so I have to disregard this pathing collision supp.
First of all there are so many things that players want when they hit an object, for example : a unit is knockbacked, if that unit hits to an unpathable terrain, it will be stunned.
If my system has this pathing collision support, they won't be able to code this.
If I still put it but they turn an instance' collision off, my system will be overloaded.