nothing wrong with the exercises you picked, it could be just a matter of volume.
i started this trap workout in my routine a year ago and ran it 6 mos. i've always had good traps, but this definitely helped them
1x50
1x40
1x30
1x20
1x15
1x12
1x12
using continually higher weight. at the beginning of the 3rd week up the first set to 1x60 but keep the weight the same. do the same the 5th week or so with the 2nd set and up it to 50 reps while keeping the first set at 60. mike miller did something similar but he would start his sets with 1x100, 1x70, and so forth working up to a couple final heavy sets of 12 to 15 reps
you could also do kelso shrugs for more depth and thickness