Regarding the case of Shadow Priests, it has more to do with the fact that Shadow Priest need to be haste-capped with any single point of haste after this cap being heavily decreasing, so yeah you'd need something else than Haste on your second trinket. Do you know how many Antorus trinkets are providing you with Crit or Intellect beyond Norgannon ? Exactly, the Catalyst and that's it. So unless you have some godlike 980 titanforged from dungeons bullshit, Norgannon will be preferred.
Itemization in Antorus forces you to play with it.
And I'd rather have the baseline 5k main stat from Golganneth instead of the 20k every now and then of Norgannon. Because with Norgannon, if you're playing a spec relying on burst windows (or ramp-up, as Shadow Priests), your DPS from one pull to another will drastically change because of this proc. Atleast Golganneth is reliable, with this 5k main stat + 5-8% total damage from the procs.