Maybe the lack of IQ and nailing focus is from his camera body .. upgrade time.
he's using Nikon's highest pixel density camera ever developed. So that can't be it.
actually the shots taken with his D90 look SIGNIFICANTLY better in terms of IQ over the ones using the D7100.
I honestly think your 80-200 looks bad at 200mm. I think you need to send it into Nikon for an adjustment I bet the glass is off spec.
edit: n/m i see youre just cropping in heavily, just showing off imperfections (although I really do think it has an issue at 200mm looking at all the images).
at 80mm this shot looks great:
13391957875_7f859c82a0_o
at 200mm the same looks like trash
13392326644_b2311d2624_o
cropped in it looks awful:
21924016686_b2e66dc75a_o