The amount of expertise and stat you gain is based on the rating of the items you currently have versus the rating that we are bolstering a player towards. If you have items above that target (for example, from high end raid gear), you get much less (or in some cases no) benefit from the bolster.
He would see around 2k expertise from level 33 gear with no expertise on it? Surely at 55 this bolster would not be like this or else PvE Raid gear as it is in 2.0 with its significantly higher stats will out due PvP gear since it will be bolstered to almost the same amount of expertise.
If that's the case prepare to lose a lot of PvPers, Endgame PvE gear should not be on par with PvP gear in "PvP" especially now that stat wise our PvP gear is useless in endgame PVE or close to useless.
Consider it this way (and it isn't quite this simple of a , but it should help illustrate our goal): Bolster defines the floor of power we want players to be in PvP and if you are below that floor, we lift you up. We have the floor currently set right around non-augmented Elite War Hero level of power.