See, I think both Wing and Knight have more place as Defenders secondary characters than Punisher, and not just because of the make up of certain teams in the comics. Punisher is defined by his very Anti nature. Anti-hero, anti-partnjer, actually comes off as something of an anti-Villian in his pre-trial DD appearances. I agree that, honestly, I can't find a vital need for him to appear in the series at all save, "well he's super popular with fans" and I'd prefer they not resort to such cameos with their first team up series. On the other hand, what little we know about Misty gives her a far more natural placement among the heroes. Coleen takes a bit more guesswork since we haven't gotten as clear a description of her role, but at the moment I'm leaning towards her being a rather more friendlier ally towards Danny than Frank, Elektra, or even Misty seems to be, and that alone leaves her in a good place to help out if Danny is in trouble.