Well you have to remember that order makes a big difference for that.
If you have an event that takes a bit of cpu, before the event that sets the sprite to mouse, then there will be some lag.
Perhaps a better workaround would be a behavior for sprite, like what we had in CC.
As I recall that still didn't fix all lag issues, as the cursor doesn't use the same buffering as regular objects.
Chances are it will be the same, if not worse for c2, regardless of what you do.