You are very much incorrect on that assumption. If Disembowel is removed
Dragoon lose 300 min to 600 Max raid dps
Bard loses 300 Pdps but Still Keeps it's overwhelming amount of utility
Machnist loses 300 pdps and since it's pdps matters more to it than it's utility to keep it competitive with bard. This job will probbaly fall into obscurity however, it doesn't lose any of it's utility either
DRG is the job that loses in this situation as disembowel's gain should be attributed to it.