I would argue that a big boshing 8 is a little outdated now anyway. The best 8s need as a pre-requisite to get through almost as much work as a flanker. Faletau, Parisse, Picamoles, Read, Heaslip etc. - what all links them when they are in form is that they are decent carriers, but they also get through a ton of work. I've noticed a shift in the way Morgan plays in that he takes on more work. He is only just behind Kvesic for the number of tackles he makes a game for Gloucester, for example. This, for me, is what is currently holding Vunipola back. He's a ruthless carrier, truly one of the best in the game. Worth a place in the England team for that alone. But he won't be one of the world's best 8s until he does more outside of the carry.