Eye test shows me he is not the same player as in 2014, and two plays from 2014 illustrate my viewpoint.
Against Jacksonville ins 2014, Dez caught a crossing route, and then jived and juked and powered for a ridiculous TD that highlighted his speed, quickness and strength.
At Washington, he did a "Anything You Can Do I Can Do Better" move by following up Desean Jackson's sprint out route that he took off for a TD with a Smoke-Screen that he juked/overpowered one CB and then outran the rest of the (admittedly terrible) Washington secondary.
I have not seen Dez make a play anything like either of the two above in a while. He ad a similar big play, but for a first down not a TD at Seattle that year.
He's still a top20 WR, but there are several guys I would take over him, and if you factor in the $, I can name at least 20.
I hope I'm wrong, and that we see more plays from him that highlight his amazing athleticism, but to me, he's more of red-zone specialist these days with occasional plays b/w the 20s.