I think I am one of them that you are talking about that wants a DT instead of a WR.
Here is my reasoning. They have a #1 WR that they paid a #1 pick for 4-5 years ago, and now have decided that they will give him big dollars to be that #1.
They gave a #3 for Tolbert, a #4 for Mingo, they just signed Paris Campbell who is about to hit his prime. They have Cropper, Brooks, and Flournoy that they may or may not be able to develop. They also really need a #2 WR -- not a #1. Draft a #1 WR and you end up having to pay him shortly and they aren't paying both CD and the other #1, so you are basically saying we are drafting CD replacement. Why do that unless you just think the new guy is a generational player....think Randy Moss. If not, then get the playmaker from RB or TE.
In the end, you still only have 5OL, 1QB, and 5 Skill players on the field on offense at any one time........Those 5 skill players can be RB, TE, or WR.....or any combination thereof. So far, I would say they have 1 of 5 in CD. So could it be a WR, yes, but it could just as easily be a RB, and increase the value of CD and the other WR with a running game.
Dallas has said they are going to get more physical, and they are not going to be so weak -- so they can impose their will instead of shrinking at the spotlight.
So if they are going to actually do what they are saying, they need to be strong running up the middle - and stopping the run, and they need to be able to power run the football for first downs at any time - imposing their will. OR they can keep getting punched in the mouth and keep trying to finesse the ball with a QB that while good isn't accurate.
The reason for DT is that is what Jimmy Johnson started with to build his defense, #1 overall pick 1991 Russell Maryland . Vince Wilfolk was the start for the NE defense. Ray Lewis for the Ravens. Sapp/Vea for the Buccaneers, Giants Dline, Randy White for the Cowboys, etc. When you can shut down the middle of the field, you make defending lots easier. Yes, they drafted Mazi a couple years ago, but so far he has busted.....will he produce now? If yes, awesome you have two guys to rotate. If no, then you need one. So drafting a 1T late in the first round is not out of the question.
IMO, the WR core will look much better with a better running game, and better blocking (health) by the OL. A more accurate QB might help as well.
To really improve the team though, you need to stop the run and make the other team one dimensional - where you can actually use the talent of a Micah Parsons instead of waste it.