On my server, there are a few people who hit level 50 before the game even launched. They are now pretty much fully decked out in PVP gear from farming Warzones since then. They are essentially unkillable now.
Against an Assassin tank (who is now up to 18k HP in PVP gear) Tracer Missiles are critting for 1200 and hitting for substantially less than that.
There is a decked out Operative (about 17k HP in PVP gear) who crits for over 5k regularly. People die from 100% HP before they get out of the initial stun. Even if you catch him out of stealth, he can just kill most people toe to toe because he chains 2-3k crits while you only hit for 800-1200.
A decked out Sorcerer can place bubbles on characters that never get broken.
At first I thought maybe some classes were imbalanced until I realized that the common factor in all of these players was that they have been 50 for over a week. I thought maybe it was just because they were level 50 and most people weren't, but my guild has 30+ level 50's and none of them hit like that in Warzones. They are more PVE focused so they don't have the same level of Expertise as these other players.
I really think that it would be best for the game if Expertise saw a significant reduction in it's effectiveness. If not, it will provide a significant barrier to entry to PVP for players and will significantly reduce the popularity of PVP as a whole. Personally, I have no intention of quitting, but it will be really hard to recruit new people to PVP if this continues and I want to see a highly active PVP community. I have already noticed that I am seeing the same people in Warzones over and over again and very little fresh blood.
This may be a problem that takes care of itself as the game evolves but I doubt it. I think that as people start getting into more Champion gear and even Battlemaster gear the problem will only intensify. A bracketing system will help matters for lowbies but it won't help the undergeared fresh 50s who get annihilated just the same as if they were level 10. Feel free to tell me why I am wrong though!
TLDR: Expertise geared players destroy people in PVP regardless of skill.