As an avid Wukong player, I highly disagree. He definitely falls into the Garen school of having only one reliable combo, but his abilities, outside of his passive, play very well together.
The clone is not meant to do damage, it's meant to be a utility ability. It's inexperienced Wukong players that believe you use it for tanking abilities, but when I see a Wukong just stop in the middle of a trade, the first thing I think is "he's probably running to his tower", 99% of the time I'm right, and I instantly pop him because he takes a predictable route. It's easier for me because I jungle with him, but I know how to use the ability offensively to run down a lane like Shack, get right on top of someone, and AA+Q+E and at the very least cause a flash. I also know how to stop juke, causing all players besides the most brain dead bronzes to back off and look for me to reappear somewhere, and just walk back and pop my Mastery V emote.
I'd definitely like a new passive that plays around his decoy, but the only thing I'd change in his kit besides the passive is nerf the damage per level on his ultimate, making it only do the 120% AD damage, but increase the tic rate from every second, to 0.8 seconds at rank one, to 0.4 seconds at rank three.
He doesn't need sweeping changes. The new runes benefitted him greatly. Predator and Ravenous Hunter made him an insanely potent diver, and I've forgone Stalker's for Trackers and Eyeball Collection with Sweeping Lens and Duskblade of Drakkthar.