I see both sides of the coin on this one, but I look at which one will help more both long term and short term. Short term for me is next season.
First choice we get Mendenhall and he can't do much at all next year behind the current and possible line without a first round line pick. Orton and Grossman look bad, and we also then have a hard time determining which WR's are a bust. Neither of which can afford to have a terrible looking year or they will be gone, despite the fact that I think there is talent there we have yet to see. Next year we still need line then, and we also need wideouts and a new QB. As part of the long term on this one we would be a couple years back before we could truly see how good Mendenhall is and by then we may have wasted some of his younger years, and we all know how valuable years are when talking about a running back.
The Second choice is to go OL even at a slight reach at 14. We do that and then the QB has some time to throw, which drastically increases the production of Orton or Rex. We decide which one we like or can have cheap for a few years, and next year that is not a pressing need but one we can develop from next years draft or late rounds this year. Benson, Wolfe, or AP all look decent this year, and we can look for a stud next year. Long term, this helps build a stud young line that we can work more towards in future years and all the other positions benefit.
I really like Mendenhall, and was excited when he was talked about as a late first round early second, but now I just don't feel as though he is the right choice. I think both short and long term we would be helped at more positions as would the overall sucess of the offense by going OL even at a stretch. Worst case, the lineman we get never pans out to be a stud, but the question is will he be worse than what we have now? I don't think so, and I think the positives of a OL are far greater than the positives of Mendenhall who I really like. We can always take a chance on Forte who could look like a stud this year if our line pick pans out. Just my two cents.