Also, with the new raid we will also get a new PvP season. That means Conquest gear gets bumped down to honor, so you can farm 483 gear(491 when upgraded), same level as Terrace LFR. And remember, PvP stats no longer cost Ilevel budget, so they are equal to PvE gear of the same Ilevel.
PD. this has no relevance if valor gear is bumped down to justice, but I don't think it will happen. What can happen is that we get new reputations with higher valor rewards as in 5.1.