The only big area that I think York has it wrong is in terms of corruption.

Warp corruption is not rust and wear, it tends to be tentacles, horns and leering mouths. It is the reason that Iron Warriors have many bionics, Chaos Terminators have tusks and Chaos armour looks awesome.

Typhus Manreaper is not just a rusted blade, it is touched by Nurgle, so is razor sharp and carries every bit of filth in the known universe and probably more (tetanus is just the beginning and you'll wish you just had tetanus well before the end).

It was a good read though, well done.