Personally I think they just have a weird system. They come out with content to push toward, such as Savage, then months later come out with content used only to catch up so you can do more savage. Where instead they could have released Alexander Regular first, then Void Ark, and then afterward released Savage in a clear line of progression. But instead we get new content that is only there to make it so we can clear previous content that people are already getting tired of.

Why not, instead, release the raids with a regular mode and hard mode like OP suggested, that way progressive raiding is a thing again, and then add something like Savage later on. They don't have the same rewards, Savage clearly comes with the best gear in the end, but then the raids don't feel so useless because half the population already has better gear anyway.