Unless a team has multiple picks in the 1st, they have to pick the top priority. Depending on who you believe, that was either of the two CB's or Parsons. Now, imagine that front 7 without Parsons.
The Cowboys had needs on the OL, the problem is they do not do well outside of the 1st in picking them. Biadasz, McGovern and Williams are still unknown and unproven. Big Smitty is this year's Sean Lee, when he can play, yowzah, but when he can't?
I think the 1st round was set when Big Smitty went out and the two magpies got to see their 160M man get thrown around and commit 2 picks, 2 fumbles and get sacked 5 times. That's called a bad day in the NFL and a QBR of 10. 10!!! Did you see that? 10, that is not a typo. I could get an 11 from the couch just throwing it away....with an occasional grounding call.
The Cowboys might need to reverse the draft for D to O this time because they will need OL and WR's. And not one of each. Those first 2 days they need, OL, OL, WR. Then back to the well on day 3.