Well.............maybe you do. But if the people in charge ever did that, we would have a major need at most positions every single year. That would be paranoid analysis.
Witten is declining and some point in 2 or 3 years from now you may have to go out and get a good TE or another WR. But until then, there are much bigger needs.
And on offense those needs are rather obvious. RB and QB. Then you have nearly the entire defense to account for on upgardes.
WR: Dez/Beasley/TWill/Butler/Street
RB: DMC/Morris/Dunbar.
QB: Romo/Moore
Witten could fall off a cliff this year. He's already declining. TWill is not a starting quality NFL WR. Beasley cannot play outside and you start 2 WR.
QB is the obvious top need.
I think Will Fuller or similar talent opens up the offense more and gives you another starting target this year and in the future. I'd like to see our runners not face a heavy box as we have for the past year and a half. Pushing TWill to the bench gives you tremendous depth. It's a good pick.
I like Elliott but only way we pick him is after a trade down. I don't think he improves the offense that much more than a Dixon who can be obtained in the third round. DMC was getting consistent 100 yard games and 4.5+ YPC when he was starting. I don't think Zeke even at his ceiling would do much better than that. More cheap TDs is about it and DMC gives those too already.