The thing is, JaJuan doesn't have to be special to help this team. All he needs to do is hit open jumpers, finish alleyoops, and play adequate team defense to help this team. And by all accounts he can do the first two and KG will probably scare him enough to at least be adequate on defense.
Remember how many players out Core Four have made to look good by just hitting open shots (Posey, House, Baby, Shaq). And JaJuan has the skillsets to make it work.