Hanifin is definitely not a "3-4 D". He's a legit first pairing d-man on a good team, albeit more of a #2 than a #1.
I don't think we have a single first pairing defenseman in our prospect pipeline. Hanifin, to me, is exactly what some here think Guhle will be. I don't think Guhle's ever going to be a first pairing d-man on a good team.
The way I see it is, it's very difficult to find a legitimate first pairing d-man that is still in his prime and while the end of his contract isn't going to be great, but even if he can't put up ~40 points every year, he'll still be good defensively.