Time will tell with Randle but I see what your saying. I just personally feel DMAC is a bust. My opinion. Time will tell...I may be wrong. I just don't see a guy turning the table in year 8 of his career. I hope Randle or the new guy Johnson emerges as a young bellcow. As for the other Murray vs DMAC....analysts have noted that Murray's per-carry efficiency was spiked by long runs last year, but he did average a rock-solid 4.31 YPC even if you exclude his 90-yard TD against the Chiefs. Murray received strong pass-block grades from PFF and held his own as a receiver, securing 17-of-22 targets for 143 yards
McFadden is very good in Pass Blocking.
I don't know what McFadden will do here, but the stats from Oakland are meaningless, especially comparing backups to a starter.
I've reviewed all of his runs on the All-22 from 2014 and he appeared to still have it physically. The problem is that he would often get hit in the backfield and that was often by multiple defenders. Their blocking was terrible and defenses would stack the box against the run because they didn't pose a threat with their passing game.
My prediction is that he will be good if he stays healthy which is obviously a big concern with him; although, he has averaged 12 games played per season compared to 13 for DeMarco Murray so there is not much difference there.
Ideally, Randle will be the starter, but his attempts will decrease from Murray's 83% down to something like 60% with McFadden getting far more than the #2 did last season. People say that Dunbar can be the 3rd down back, but that is a good role for McFadden because of his Pass Blocking ability.