To me it is less about the RB and more about the backup QB spot. Given the circumstance that we don't seem to have a receiver outside of Dez that can do anything on their own and as such teams don't dear the passing game, I think the running game has been fairly decent. Running into 8 man fronts isn't an easy task for any OL.
I do think we could have added a RB in the draft, there were guys in each round that could have been taken. I would have let Randle go after the shoplifting scandal..when you threw in the other crap that he got suspended for it was a horrible decision to keep him. Chris Johnson was begging us to take him and would have been a good pairing with McFadden.
We KNEW that Weeden was not the answer and we stood pat. That was an awful move. I am not sure what legit options were available to us and I really don't feel like researching it.
The big killer early on was injuries. No way to get over that. Romo, Dez, Gregory, Scandrick, etc. Romo was able to rescue us the first two weeks, but when Gregory went down, our pass rush became worse than it was a year ago. We literally had Mincey until we got Hardy from suspension. McClain being suspended and then being out of shape was a killer. And Lee's injuries have been tough. We can't count on him. Hitchens and Church have been fighting through injuries all year. Free and Leary were not 100%. Hanna has been fighting an ankle injury since training camp. Can't remember a year with as many key injuries. At times, I think it is a miracle that we have been close in as many games as we have been.