My bold prediction is TE with pick #1. This is NOT based on need. OL, DL, RB, and WR are all arguably bigger needs.
The way I see the draft unfolding, at #26, the elite players at the "need" positions listed above will be picked over. Dallas might be looking at the 8th best DL available for example. At the TE position, Dallas might possibly be looking at the second best TE in a draft loaded with good ones. If the goal is to grab an elite talent in round 1, the BPA could very well be TE.
To be clear, I would rather be beefing up both lines.