Why is there no job with rogue as a secondary class?

[DestinovaTrueblade]

They would have probably nerfed non traited version of all those skills if they were x-class skills. They did that for BFB and IR back in 2.1 to nerf Bard

Shadeshift - would have prb been nerfed to 10% as a x-class if tanks can get it, consider that SE thought 18% stone skin was too much mitigation. For MNK and DRG, its better than Forsight by a mile.
Mutilate - strictly better than fracture for 20 pot, but drg or mnk still prb wont use it much for the same reason they dont use fracture
Assassinate - would just replace Mercy Stroke for MNK and DRG
Goad - would make BRD/MCH angry if multiple jobs can now restore each other's TP, hell, it would reduce NIN's own utility value, so I dont see this as possible without it the non-trait version being worse.
Jugulate - for the most part would just be an extra pot 80 attack, since silence hasnt been useful for a pretty long time

Melee would make sense, but while i would love to replace the Marauder x-class i use on DRG and MNK with Goad, Assassinate and shadeshift, they couldnt do that without nerfing any of em otherwise they'd screw over NIN.
BRD and MCH are better off with what they have currently, their current x-class is too good to pass up.
Caster having NIN x-class would not only be odd, but would be mostly impractical anyway.
Healers having NIN x-class would be even weirder. Not that any of them would want it, since CNJ, THM and ACN skills are rather indispensable to them.
Shadeshift and Goad would be amazing for tanks, but I doubt SE would straight up buff all 3 of em like that.