This was a pretty good read. I agree in that it seems like RTR's biggest effect is going to be graveyard hate spells. I think deathrite shaman is another pretty playable graveyard hate card that you didn't mention. That would put it at 2 pretty much guaranteed new GY hate spells, and 2 at least fringe playable graveyard hate cards.
The two cards I disagree with you which both look good in theory, but I dont think they are playable in reality.
While vandalblast looks amazing in theory when you overload it chalice at 1 still counters it so I dont think its really playable over ingot chewer or shattering spree.
Again treasure find looks like a slightly more cost prohibitive regrowth, but is regrowth even playable anymore with all this new graveyard hate? Unlike snapcaster it has no use outside of recurring spells. You even said in your analysis
I usually play the allotted one copy of Regrowth
not you guaranteed play the allotted regrowth in cobra gush.