There are no bad players. Just bad choices in spells used and attitudes displayed in a given situation. You can fix a bad spell choice in any situation, be it pvp or pve. I myself adore dungeon runs and the new raid finder. I'm even tanking more now than ever before and loving it. My guild mates however, while they are willing to be dragged into a raid finder run or two and down Deathwing, love pvp a bit more. They aren't bad by any means though. They asked me what they needed to know for the fights and did it. We downed every boss the first time. Bad attitudes however are something that can really suck the fun out of things. Like the tanks you get partnered with who want all the attention and be "main tank". There is no main tank really anymore. Even in raid finder you have the second tank to share the burden of getting your teeth knocked in. Oddly warrior tanks suffer this delusion the most and are rather a pain to put up with. However the best tanks I've partnered with have been warriors but they also knew how to share the damage.

Since I don't like posting twice I'll mention here that maybe raid finder is TOO easy. Morchok doesn't stack his debuff enough to make switching that relevant. The ball on Zon'ozz doesn't even need anyone to bounce it around since it goes to the boss after 10 stacks. The slimes normal worries about are often disputed over actually mattering in raid finder on Yor'sahj. Ultraxion and Blackthorn are actually fine since wipes DO exists on them. I'm actually disappointed doing a barrel roll isn't needed on the Spine of Deathwing. And on Madness a decent group of dps can down the limb below 50% before cataclysm even starts. I'm not complaining about it being too easy and maybe I just need to switch to normal but that's the thing. Raid finder almost feels too simplistic and anyone shifting to normal has to learn to do things CORRECTLY in order to succeed. In fact that could be one of the few failures of raid finder in terms of its intentions. If it was supposed to also serve as a tool to prepare for harder modes, it doesn't work if mechanics can go by the wayside and be ignored.

TL;DR: The only bad players are the ones with bad attitudes and we can fix anything else. Tanks need to learn to share when another tank is present and everyone wins. And it's possible raid finder is over tuned since you can ignore entire mechanics and still profit so switching to normal becomes a hassle.

Still TL;DR: Players like kabshiel are the real bads and either raid finder is broken or we the players broke it.