You're typically not going to get a player who improves your blueline in return for a late round pick. It's a 5th round pick for an NHL Dman, I just don't see why it's getting much attention.
Plus we both know that hockey GMs care way more about intangible factors than their counterparts in these other sports. The Sens aren't really built to compete yet and are set to have a pretty young blueline group. They brought Gudbranson in to be a veteran presence on the ice and in the community, plus add some physicality to insulate those young puck movers. He saves uncle Eugene 1M assuming they only spend to the floor, I don't doubt at all that added to the appeal.