Murray had 1,845 yards this year. Peterson is the best back in football, but how many more yards is that? 300-400 more? Maybe not even that much, given he'll be 30 next year. Can he tote it 392 times, being 3 years older than Murray? Lots of questions to me.
There's also this: if you believe what's out there Murray is being offered 4 million per year by the Cowboys, he wants 30 million for 4 years, that's a little over 7 mil per. Adrian Peterson makes $12-15 million per year. Giving that kind of money to a 30 year old running back costs you the majority of the 15 UFAs on your roster. I'd prefer not to sign him.
Get better on the d-line, keep building the trenches. If you build these lines up, you build a consistent championship caliber team. I want Witten and Romo to get a ring as much as anyone, but I also want to transition to the next qb without going 2-14. You can do that by being extremely stout on both lines.