No, he seems to be applying the M+ dungeon mechanic to Raids and capping it at +20 to keep the difficulty of the raid viable for longer.
That’s why I prefaced my reply with “kind of” doing it with Fated but with Fated you could carry the viability of the raid indefinitely. You would still be able to mog run old raids but still have the option of applying a Fated tag to run it at a current ilvl difficulty. Think a step up from Timewalking. I think this is the route they’ll move after Season 4 which I view as the test bed.