Kakko is tailor-made to break analytics models.
He's great at regaining and keeping possession, but has absolutely zero skill at doing anything with said possession.
And I understand there's value in keeping the puck out of your own end, but the xGF models don't adequately reflect how hopeless he is at generating offense.
Is he still a "plus" player? Absolutely, but his value is that of a bottom-6 shutdown winger. If another team values him as something more, you take what they're offering and run.