How do you figure? PvP gear will still have iLvls above 496 it looks like. Just when in a controlled PvP setting everyone will be scaled down to a certain point. Giving everyone more baseline resilience isn't going to kill it either as you'll have more PvP Power in PvP Gear so you'll be able to wreck them quicker.
Also, people are assuming way too much without knowing anything other than two lines in the patch notes.