If he is going to play on the top 2 lines and also in the pp, then he needs to remain a possible scoring threat. Whatever threshold is the minimum a player can remain a realistic threat, that's what I would be happy from him.
The team doesn't need another goal scoring player. It needs leadership and toughness in the top 6. If he scores 5 goals and the team does well around him, I'm happy. If he scores 30 and the team around him crumbles, I'm not.
So, I'll be happy with what I consider to be a minimum a player can score and still demand attention from the defense pair. 15. And, depending on whether he plays 2nd line or 3rd line. 20-25 assists.
For a total of 35 - 40 points. That, to me, is a successful season. Given, of course, that he brings the intangibles every night.