Me personally I think all Heroic Raid Bosses should be for the hardcore players (which isn't me). I don't think heroic raid bosses should be nerfed so that all players can experience it. Normal raid bosses, sure, nerf away so that all can eventually see the content and experience the end game. But leave the heroic raid bosses to for the hardcore guilds. I'm totally satisfied to not ever see a heroic boss and continue just doing normals. But that's just me. For me, if left this way both satisfies the casuals and the hardcore guys who likes bashing their heads against challenges.
That said, I do feel based on what I've heard and read, that maybe they did make the first six heroic bosses too easy and the final way too hard. So they probably should nerf the last heroic boss but NOT to the point that it is a breeze. Still make it challenging for those hardcore players who want the challenge.
And I know you hate the use of Hardcore and Casual, but hopefully you know what I mean.