I tried playing my affliction resto lock but it's so so so so fucking immobile. In group pvp you have 0 ways to escape a 1vX. If you remain behind for whatever reason, you get piled up on. Even shadow priests and elemental shamans have decent gap makers. Can't play like this.
For DDoS, unfortunately, there isn't a lot you can do other than avoiding public chats. Make sure that if you log onto a voice server, that the admin isn't going to share your IP with those you're playing against, etc. Would be nice if blizzard just made a better voice feature as part of the game so that you could use battle.net as the voice chat server for those who want to use voice.
I'm generally a competitive person, but not to the point where I want anything to dominate my life. Those esport teams are often very competitive and they'll try just about anything to gain a competitive edge. It's not limited to WoW...in NASCAR, for example, certain teams would run nitrous when most cars were plain motor, and that nitrous shot gave them an extra 100-200 HP which was enough to win races...so then it was banned. Then tech like traction control came along, giving drivers who have it an advantage over those who didn't, and it too was banned from certain sanctioned races.
I guess it's a matter of grey area in some cases, but with WoW I'd say it's almost exclusively cheating.
That's another giveaway of bot-users but sometimes it could just be that one class is so grossly overpowered that you can basically skey and keyboard-turn your way to a 2K rating. In MoP my BM hunter was a total joke; I mean OP as hell. I played with a combat rogue and we literally went 50-0 in 2v2 simply because the hunter's damage was so ridiculously high, and the rogue's CC in addition to my own made it impossible to counter. Like a 99 cent taco, it's food but it's not satisfying.