Playful/trickster still needs to not be effected by CDR.
You can do it Riot.
Make the ability Static.
He is lacking points of vulnerability with how short the cooldown is when CDR is added in.
He is everything akali wishes she could be again.
Think of this as a "frustration" nerf much like Zed has on PBE.
Getting kills is alright. Getting out consistently when going into 3+ enemies because of a 4.8 second cooldown ability is not.