PvP bolster in 2.0
There was a correct developer blog about PvP and bolster in 2.0 link here.
The most important parts:
The hypotetically fixed the naked boolster, so it should always be better to use items instead of being naked.
They fixed the war hero(WH) and elite war hero (EWH) gears, so the expected effectiveness in warzones the next: PvE gear/WH/EWH/Partizan/Conqueror. The gap between these hypothetically will be less than before. Not recommended to use older PvP gear than WH (Battlemaster, Champion, Centurion, Recruit)
They removed the expertise of WH and EWH gear at out of WZ and gave some primary stats. Only exception is the expertise crystal. They recommend to remove that and change it to endgame PvE crystal.
They said DO NOT MIX PvP and PvE armorings/mods... in one item, because it will be worse than a pure PvP or PvE item. But you can use mixed gear (PvP helmet and PvE boots), because the bolster is working separately on every items.