I would absolutely re-sign Kuhnhackl. He's been playing in a mostly defensive role (middle 6 at even strength, a lot of PK time, very little-to-none PP time), so clearly they value what he can bring in that role and/or are cultivating that part of his game. But the offensive skill he has will never go away. He has legit talent, legit offensive instincts, good passing ability and an absolute whale of a shot. I'm not sure exactly of their mindset with him, nor what he is like off the ice or in the locker room (personality, commitment to conditioning, etc.).
But if he's at least proving somewhat useful in a defensive role and can get better and mature overall, then it follows that he'll start getting some more offensive opportunities. And if he does, then it also makes him less of a "top 6 or bust" type of player. I would definitely give him another 1 or 2 years before I write him off. He he doesn't take a nice step forward next year, then I'll be ready to forget about him. At the moment, there's still a part of me that fears he could be a breakout player somewhere else if he left tomorrow, so I'd like to give him at least 1 more season. He's definitely not ready for a call up this year, however, in response to the original question raised.