I've been playing online games forever. I mean really, since the beginning. No kidding. I played first person shooters for ages and then started playing MMO's.
One of the reasons I left FPS games is that it is really difficult to prevent players from cheating. Due to the way various aspects of the game are assigned to computers, it is very difficult to keep players from doing things like running aim-bots (code that gives the player perfect accuracy) or invisible wall cheats (allowing...well you can guess, but it also applies to seeing through fog and smoke). It seemed like about the time I stopped playing them, that a good one would be ruined by cheaters two weeks after it came out.
MMO's make it harder, but not impossible, for cheaters. There are still problems, but at least the successful cheats are different.
Anyway, there were things I liked about MMO's, but some things I missed. One of the biggest things was player versus player combat. In FPS's that's all there is (I treat the PvE aspects as more of a tutorial). Sometimes everyone against everyone else, sometimes teams, but most of the time I was playing against other players.
I started off in MMO's as a PvE player (not much choice in early WoW as they didn't have any PvP on PvE servers). I missed PvP. Over time, I've spent more and more time playing against other players. This was pretty much true of all the MMO's I sampled.
I really enjoyed the PvP in MMO's and spent a lot of time playing them...but you know, there's just something not quite there with PvP MMO's. It's been bugging me for a log time. It wasn't just one thing, it was as if the MMO game designers just didn't get. They didn't get it, or the compromises they needed to do for a mixed PvP PvE game were so great, that they gave that appearance.
I got really frustrated with the games I was playing. All the MMO's seemed to be missing the point. In design decision after design decision it just seemed like they had headed toward something good, then went right on past without stopping. I started recording where I think they went astray, expanded on it and put it all into a book.
It's now on Amazon as a downloadable e-book. Here's the link Epic Failure - PVP MMO RPG Game Design. Actually I named the book "Epic Failure - Player Versus Player Massively Multiplayer Online Role Playing Game Design". (Apparently the "G" is silent).