Well back when Expertise was relatively weak, it was confusing people into thinking that their PvE gear is better than PvP gear and you still have the same problem. I think they made Expertise so big so that they've a bigger range of values to work with. Obviously UW gear would have no shot at being competitive against Conqueror if there isn't Bolster. You sure won't going to do 60% more DPS for wearing UW compared to Conqueror, and people would complain (rightfully) that their best PvE gear doesn't even stand a chance in PvP.
Yes, and because of that, bolster is required to give expertise. The entire point of making exp linear was so that pve stats were bad compared to exp.
Bolster is there to give pvers a shot, exp is there to not give them a shot.
Right now exp is strong, but bolster is even stronger, canceling it out.
Get rid of exp, and make bolster weaker so that you have less code and balance to work with.
I just... the philosophies contradict, that's all. Its sad imo