First of all let me be clear he still has his moments, however lets take a close look at him
His Q is still the escape king, and godly at initiations but the damage on it has been reduced to pathetic levels! Lets be honest the damage on this ability is completely gone! At rank 4 its essentially a crit and nothing else!
Suggestion - Add a feature that you gain 10/15/20/25/30% Attack speed for 3 seconds after hitting a target with his Crit
His W has been hit the hardest of all, and honestly it deserved it due to the toxic gameplay it created however there are better ways to fix the toxic gameplay while making this ability not worthless as it currently is
Suggestion - Reduce the stealth time to 1 seconds, add a feature that if 2 boxes target the same target the damage of the second box is reduced by 75%, increase fear duration to 0.7/0.9/1.1/1.3/1.5
His E has really pretty poor scaling and the stats on the additional effects have been reduced pretty significantly, honestly tho this is probably his best skill so it doesnt need much
Suggestion - Reduce the cooldown to 6 seconds, the active effect now applies double the effect of the passive slow, damage changed to total AD instead of bonus AD
Finally his R, there arent many changes needed, just a few bug fixes such as the clone will now actually appear to be holding the correct items shaco has and the clone will be affected by Shaco runes and masteries (assuming these werent fixed yet)