I think Vince will give Cody a decent push at the start (maybe even a championship run) but, WWE fans will get tired of him once the excitment of getting an AEW guy goes away. Cody's just not that good without the gimmicks.
In AEW, Cody had the power to add all of the bells and whistles to his matches. Cody loved to overbook his matches. Crazy spots, outside interference, tables, tons of blood, celebrity interactions, fire. It's like he knew that he had to do the most for people to like him.
In WWE, Cody won't be able to hide behind the gimmicks. He won't be able to name drop the other company in every promo for a pop. He'll have to rely on his own ability without the extra privileges he got in AEW.