It felt like Whedon didn't know where to take Hulk from where he left him in Avengers 1 and decided to just undo it all.
Rampaging, hexxed Hulk aside, I didn't like how they made him even more animal like when he could clearly speak and think critically in A1. Widow had to fearfully approach a raving mad Hulk to calm him down, like he's a rabid dog.
But in the New York battle he was not acting threateningly to any of his team members while idly standing by them. He followed orders and waited patiently in the back of the group as they apprehended Loki. If the Schwarma scene is to be thought of as canon, Hulk transformed back shortly after, presumably without anything remotely like The Lullaby. He makes a snarky comment about Loki being a god. He hits Thor, which could be considered him attacking his own team, but he did it in a smug, casual fashion because Thor is his rival. He pulls a Leviathan away from a building full of people. He could have just punched at it if he was truly just an animal but instead he makes an effort to steer it away. He saves a team member.
The intelligence was actually always there but not really carried into his next appearance. Hell, we could have gotten a gradual evolution to how he is in Ragnarok if Whedon didn't get cold feet about the arc he had started for Bruce/Hulk.