The DB for KC last year. Patrick Peterson, although largely due to his ridiculous punt returning. Hell, I'd put Roy Williams on such a list.
Not that it means anything but Lynch didn't exactly do anything worthy of a high pick investment as a rookie. Generally, most rookie RBs aren't massive impact players their first year. There are certainly a number of DBs who had great impact if you broadened it to the first 2, 3, or 4 years as you would have to in order to include Lynch in the discussion of an, "impact player".
One or the other is really only part of the equation. The next best alternative at the position you didn't use the pick on is the other half. Does Zeke give you so much more than the next best alternative (either through the draft or free agency) that passing on the DB is worth it? Who is currently the next best alternative at the DB position? Brandon Carr? Morris? The DB for KC last year had 8 INTs. That's 1 less than Carr and Claiborne have accumulated throughout their entire careers in Dallas. That's combined. If the DB was able to get 6 INTs, that's still more than these two have combined since 2013. If he got 4, it would be 4X as many as these guys have over the past 2 years.
I have little doubt that Elliot will produce. He's a stud. I question whether or not he'll produce to such an extent that the additional yards and TDs gained over the next best option will actually make as big of a difference as additional turnovers and good CB play would. There's obviously less risk with Elliot but it just doesn't seem like the net gain over the next best option is anywhere close to what it would be if Dallas would have taken a DB who played up to the pick.
I'm not upset with the pick but it's far from being as clear cut as saying, "Zeke is a sure thing", because even if that's true the team may not be gaining a significant amount relative to the next best alternative. If another RB could have given Dallas 80% of what Zeke can, the team would have probably been better off going with the DB. That extra 20% probably isn't going to swing many outcomes simply because the NFL is a passing league. Any boost to the running game will only go so far when the running game only accounts for 30% of a teams offense. That's what it was last year. Just under 31% for yardage and TDs.
