To me it's pretty easily:
Hughes
Dahlin (1 and 2 could switch, but it won't be because Hughes regresses, it will be if Dahlin goes supernova and he showed some signs last year)
Dobson
Miller.
To me, Miller is clearly number 4 which is good, but some Rangers fans get overzealous and place him above guys who are clearly out of his league currently.
I'm not a Bouchard believer, didn't want us drafting him (wanted Hughes and was pleasantly surprised when he fell to us), think he's not competitive enough with the puck and too slow.
I see him as a bit of a poor man's John Carlson (and I like Carlson, but he's not so good that a poor version of him is elite).
Bouchard's puck movement and shot will keep him in the league for a long time, as it should. But he's the kind of player who will need very particular deployment whereas I see Hughes, and Dahlin as top pair D who can play with almost anyone (some of this is projection, but they're not far from this), Dobson as a very legit top pair D, and Miller as a fantastic number 2 when all is said and done.