Those are all valid points.
I agree that the technical documentation about the OS internals, useful only to the developers, doesn’t need to (shouldn’t ?) be at the same place than more general documentation pertaining to the end user or the non-programming contributor.
I also think that using the main website is the best way to expose said documentation to new members of the community.
And of course we should not move a page or document without putting in place some kind of redirection.