Slavin was good last year and great this year. Regardless, he's currently the only true #1 defenseman on that list which is why I put him first.
Trouba produced at a similar clip (1 less point) to Slavin in 22 less games as the Jets #1 defencemen this season. If Slavin is a #1 defencemen then Trouba has been for awhile. Lindholm as well. In fact both have proven more than Slavin to this point. He's good but lets slow down with him being the best when he hasn't even proven he's better then those two yet.