I don't know where a guy who has diminished raw ability and was never a precise route runner gets a job in a modern NFL offense honestly. Beyond being like a 4th/5th receiver for depth.
Peak Dez was very good with Romo, a guy who was good at (and often just HAD TO) freelance. But he's way past his peak, and as far as I know doesn't have technical ability to fall back on now anymore than he did in 2014 (!)
I don't hate Dez like a lot of people but I kind of just don't see how it adds up to anything to have him come back.