Was the removal of stacked slows good for the game?

With all the discussion of AD carries being really terrible, I'm starting to wonder if it's okay for Darius to run at his opponent with near impunity and destroy them. Part of me feels that the removal of stacked slows is to blame for this.

Might also create an avenue for assassins, whose mobility is not barred by slows, to make a niche for themselves.