@Riot, CC should stop dashes
Lets be honest, there are way too many dashes in League. Then there are immobile mages who has nothing to deal with dashes. Mages use their cc, then the enemy champ gets into melee range to them anyway. Those mages have no counterplay to dashes.
Dashes should not be used without thinking. It is a core mechanic for many champ that has to be used intelligently(cc is also mage's core skill and most of time only defence). For example, if that J4 gets stunned while doing e q, he should stop where he was stunned. Giving him the freebee to make cc happen when he finishes is useless because all he will do is to just use his ultimate.
tldr: CC should prevent dashes because they should be rewarded for landing it, dashes should be used more intelligently then to use it whenever they see them because they know nothing will stop them from engaging. Also, CC duration still ticks when they are dashing, so it basically negates the entire cc just because they were in the process of dashing.