I think he is #1 at 154.
He was the first to beat Cotto at 154 who was #1 & had a world title, Trout beat Cotto who was coming off a loss. I can't think of another 154lb fighter with a decent win over another top 154lb'er...
I mean who else has a decent win at 154? Kirkland over Angulo...
Cotto is a much better fighter and a much better win IMO
If Molina had got the decisions, I'd have him at #1