No he's not, Seabrook is a #1 Shutdown D, Ryan McDonagh is a #1 shutdown d, so is Shea Weber, Chara was a #1 shutdown d. Hammer is not one of them.
I think your definition of #1 is too narrow, like a #1, vs. "true #1". Hjarmalsson has been used by the Hawks in a shutdown role, Keith and Seabrook tended to get slightly sheltered minutes compared to Hammer and Oduya.
Hjalmarsson isn't a #1, by the simple fact that there are 30 defenseman better than him. He was great in the playoffs but he's really a #2 guy. A good support defenseman for the top pairing, or can carry a 2nd pairing.
He was actually great all of last season, not just in the playoffs. I didn't really make a list of top 30 defenders, I would assume he'd be in the 25-30 for me, but I think there's really only 20 or so guys who're definitively #1s, the others are dependent on preference. So you'd be perfectly fair in disagreeing. But I think Hammer could carry a top pairing on teams with weaker defence. He'd automatically be the best guy on some teams right now.
You're stating a ton of opinions as facts, and I disagree with most of those opinions, so there's really no sense in wasting my time any more at this point.
They're all my opinions, I didn't think I needed to preface all opinions with "It's my opinion that blahblahblah". Player X is better than Player Y is almost always an opinion when it's sort of close - just look at those ranking threads or polls, it's nuts. You're free to disagree.
Edited to add in response to you guys:
Some of Hammer's stats compared to the 3 listed by 1GuinFan:
Including some other defencemen:
Hammer lines up very well with some very good dmen, I included Letang and Martin from the Pens (as Maatta played too few games). I think he's excellent defensively, he's just very lacking in the offensive department which is why I have him on the low end of my #1s.