Twisted Fate needs a skill on his E and he'll be perfect
What I suggest: Leave the attackspeed steroid (his base attackspeed is stupid slow he needs this)
Twisted Fate shuffles his cards and picks one at random granting him a temporary bonus(Doesn't work like PaC where you can choose. It cycles through for X amount of time then stops on its own after the time duration it fits his gambling theme perfectly) Goes on CD after the duration of the skill has ended
Blue Card- Twisted Fates next attack within X amount of seconds deals bonus magic based off his AP)
Red Card- Twisted Fates next attack within X amount of seconds steals X amount of enemies movement speed (like malphites Q) amount is based off his AP
Gold Card- Twisted Fates next attack within X amount of seconds stuns his opponent for .1 second increasing by .1 second for each rank into the skill
How the skill works: Cards float around twisted fate (just like they normally do when his E proc is up) only they constantly switch through the blue/red/gold colors until the skill autolocks one for him. Then the floating cards change to the selected color. (Is visible to enemies) the player has 0 control over the skill other than activating it to cycle and nothing can effect which card color he gets other than pure luck.
Wrap up: This skill gives him the small boost he need without turning him into a monster
Blue card - Gives him that tad bit of bonus damage he needs to match well...everyone
Red Card - Gives him mobility while not making it as stupid as
Gold Card - Gives him the ability to actually survive an engage on him for once. While the time isn't too big it does give him incredible outplay potential with his gold card. (Say use the stun from this ability then use PaC and stun a 2nd time baiting someone.) It makes no sense that his only ability to survive basically every single mid laner is his PaC in which once its down he's vulnerable to everything
I think this idea will put Twisted Fate in a perfect spot and would make him the bar for how other mid laners should be. It would complete his kit and still be thematically correct. His E is just so lackluster and doesn't make any sense. His terrible range is already a disadvantage so why not give him an E so he can be on par with everyone?