Which pack? Doughty, Keith, and probably Karlsson are the only three guys I would say could be put into a tier above Letang. And I'm not even sure I agree with those three. But I don't even see an argument for anybody else being clearly ahead of Letang.
Karlsson is the best offensively - That's about ****ing it.
Doughty is fairly solid offensively and defensively but he's good at both, not exceptional at either.
Keith is amazing at the defense part of the game, offensively he's fairly good.
Letang is exceptional offensively, just under Karlsson, and he's on the level of Doughty and just under Keith defensively.
To me it's Keith, Letang, Karlsson, and then Doughty. That's not even being some homer about it, that's looking at each players skills and what they bring to the table. I like Doughty, but I feel like he gets sheltered by his partner a lot as well, Letang is switched with partners so often he rarely gets that benefit, when he messes up, it's more visible it seems. Karlsson is always anchored with a stand out defensive defenseman and Keith is always with a guy that covers his ass too.
Letang? Not so much.