The Robbins-Martin statistical argument is a good one. It's also kind of a zero sum game--perhaps we simply had our act together more as a running attack by the time we faced the Oklahoma schools, and the more senior Robbins got the nod, and hence the carries and yardage, that would've been there for LJ? Impossible to know. Early in the year, with the blocking and scheme abyssmal, Martin appeared to be at least somewhat better at finding creases and breaking tackles.
Accordingly, I still see RB as a slight downgrade to a push that could even be an upgrade IF we can remain healthy--a significant problem last year in addition to all our other issues.
Beyond that, it's fair to base your ratings on what has been demonstrated vs. what is hoped for. That said, it's normal, not pie in the sky, to anticipate players who have demonstrated their ability early in their careers to take a step up with added experience. I think that's particulary true of young guys like McKenzie, who showed very exciting flashes and whose absence was felt when he got injured.
Like I said, your review is probably the best I've seen. Combined with what I think is a slightly more amenable schedule and what had sure as heck be a sense of urgency throughout our program, we will probably still have to exceed your ratings in some key areas.
It's not something I would ever bet the farm on, but it isn't crazy to hope for either. I see our range as between 4-7 wins and will hope for the upside until hope is lost.