I plotted out the Oathgate locations to see if there might be some pattern:
I was hoping it would match up with points on the Radiant chart (or something similarly simple), but I can't see anything. Hopefully someone else notices what I can't.
I used the following labels:
X = Oathgate, exact location known
? = Oathgate, exact location unknown
U = Urithiru, approximate location
and here are locations listed out as the high storm blows (right-to-left):
This does actually make sense. We know that each of the Silver Kingdoms had one Oathgate, and each of those locations corresponds to one of the Silver Kingdoms as demonstrated on the map below.
It may look a bit like the Oathgate in Kurth is part of Iri there, however, the colouring of the map would indicate that the island in question (as well as all of the Reshi Isles) was, in fact, part of Rishir.
So, as it stands, I don't see any major issue with the proposed placings of the