Question is who are you trading for? If it makes sense to make a deal i'm all for it. Problem is this idea that the Cowboys don't get value out of their 2nd rounds picks just isnt true though. Our last three were Williams, Joesph, and Diggs. I dont think anyone would want a redo for at least 2 of those 3.
Aside from that Hill has developed into a decent rotational guy. Not what you want out a 2nd rounder, but not a complete bust. Same with Connor Williams. Awuzie has turned into one of the better CBs in the NFL since leaving Dallas. Randy Gregory was a bust, but no question the talent was there. DLaw was well worth a 2nd.
Over the last decade, 2nd round drafting has actually been pretty good. The bigger problem for the Cowboys has been getting the most out of some of those guys.
Now any team trading a wr to the Cowboys is going to assume that 2nd round pick probably falls in the later part of the round which I think really matters. 2nd rounders in the top half of the round gives you a chance to get a guy who you had a first round grade on who slid. You get outside the top 50 picks and that starts to change. It's likely why the 9ers had to give up a 2nd + a 3rd, 4th, and 5th for CMC. If you want a difference maker it kind of seems like the bar has been set there, unless you want to go with the 1st or you're also taking on a bad contract or something like that.