My first MOs (pre-massively) were MUDs, and every one of them was destroyed by the introduction of non-consensual PvP.
These experiences (combined with my experience with persons running amok in paper & dice RPGs - see my letter in Dragon #143) firmly established my distaste for PvP in general, on principle.
If someone states they prefer non-con PvP, I automatically deduct 100 points from their IQ, 30 years from their maturity level, and assume their real-life alignment is Chaotic neutral at best, and hide my wallet.
PVP Games like Guild Wars revolt me on a primal level, and WoW isn't much better, since the whole level treadmill seems to be set up for the express purpose of becoming a PvP character (And, you hear the news of the Chinese player revolt in WoW brewing over bad customer service?).
That said, I've actually been playing UO for 3 years, and have not found an end to enjoyment yet. I don't HAVE to go to the PvP areas, the characters are mutable enough to change over time (no levels or classes, and soulstones allow swapping skills between characters on the same account, so trying out a new skill template idea is easy - and I play some of the most "flying in the face of convention" templates ever seen in the game, and make them work), and the recent expansions are not too many, not too fast (though the game is starting to have power creep problems). Plus, they've been averaging 6 weeks between update publishes, for the last 3 years, 22 in 30-36 months, compared to 17 in the first 5 years of the game (upside-down compared to how most games, where the updates get slower as the game ages).
And, I actually PREFER 2D overhead view over any 3D or first-person view games (especially 3D first-person games), from my roots playing things like X-Com, JA2 and Fallout. When I have a full immersion environment, THEN I might like them - but until I have a game on the level of "The World" in ./SIGN, complete with VR gear, that's not an issue.
However, There is a movement afoot in the new Dev Team to institute a massive equipment nerf to back down from the item-based game that PvP has become, but it may have a chilling effect on those of us who chose to be PvM types exclusively, as the good pieces of equipment come from the PvM and Crafter players.