You might have heard of this week's Ilium disaster in Star Wars: The Old Republic. Basically Bioware changed the rules how PvP is handled in a specific PvP zone, and got surprised by the consequences to a degree that they needed to emergency patch in a hotfix. It turned out that if you make PvP very unrestricted, with very few limitations except that you can only kill players of the other faction, players will react by playing not nice. In this case it was possible to camp spawn the enemy faction, and people did so in large numbers. The previously barely reported faction imbalance between Empire and Republic, with Empire outnumbering Republic up to 6:1 on some servers, of course also played a big role.
It is stories like these why I don't play unbalanced PvP. I only ever create characters on PvE servers, and I avoid games which don't balance their PvP, except for testing. The problem is not even necessarily the games, but the problem is that people online don't play nice. In the real world people set up things like amateur soccer matches, where without external pressure the players themselves prefer an organization which is as fair as possible. In online virtual worlds people always try to make PvP as unfair as possible to their advantage. The Council of Stellar Management (CSM), a player-elected council who represent the views of the members of the EVE Online community to CCP, recently stated that in their mind the "unique attraction of EVE is "you can grief people" and "it's not a game for wusses"". People pay money for the privilege to grief other players, that is the kind of world we live in.
There are a lot of good PvP games out there, but if you look closely they are good because in some way the game developers forced balance into the game. Unbalanced games only hold on to their players by offering them safe zones, which is what Bioware now patched into SWTOR. World of Tanks is an extremely well balanced game, which promptly makes some people complain about that balance. It appears that there is a large demand not for games in which players fight against other players in some balanced way with uncertain outcome, but rather for games which allow you to completely crush your opponents without ever giving them even a hint of a chance.
The problem with unbalanced PvP in virtual online worlds is that the losing players have the unalienable right to log off. Bioware had to patch Ilium because Republic players simply logged off, or found the trick on how to sign up for a warzone and use the emergency fleet pass from there to escape Ilium. If the zone hadn't been patched, it would have become deserted within days. Nobody wants to play the loser without a chance in a virtual war. If everybody wants to crush their opponents, and nobody wants to play the crushed opponent, then maybe it is time for some new business models: The predetermined winners could be made to pay to win, while the losers would be paid to lose. In a way Free2Play games with "pay to win" items in the shop already function a bit like that. Or people need to play PvE, because computer opponents don't mind getting crushed all the time.