First this is an MMO, gear progression is the main pooint to keep playing.
Second, removing expertise would require all gear to mirror pvp gear in health and damage, what this means for all of you who seem to be crying expertise is horrible is you will be getting hit harder and the damage you deal would do less in terms of your targets total life.
The reason you lose is because they have gear and you have none.
If there was no pvp gear people would roll over any who doesn't raid with their pve loots. So that is why there is pvp gear, they put a stat on it that takes away from damage in pve so you can't pve to pvp, but you can pve to pvp.
It's not expertise it's the gear, a person in full t1 raid hear would roll you just as hard as some in champ gear.