Here is a blue response to questions about 14 being a magic number you can read the entire post at http://us.battle.net/wow/en/forum/topic/10894620000?page=1
"You can read the latest hotfix notes here: http://us.battle.net/wow/en/blog/11944164/542_Hotfixes_December_16-12_16_2013
Fun fact: The hotfix has actually been active since just before the weekend, but it didn't get caught in the prior round of hotfix notes. It's no surprise that it went largely unnoticed, since most all of the abilities with actual breakpoints going from 14->15 are things with very minor impact (Protectors' Shadow Word: Bane, Nazgrim's Bonecracker, Hisek's Multi-Shot, etc.). There are indeed a couple of more impactful breakpoints on Garrosh's Touch of Y'Shaarj and Sha of Pride's Imprison, but those both occur at raid sizes well above 14, and randomization isn't the correct solution to either.
The 14-player "magic number" is actually a fairly interesting social dynamic, since there never was anything particularly special about the number, and now there really is objectively no advantage. As we've said in the past, there's certainly nothing wrong with wanting to form a 14-player raid, but if you're turning away strong players or friends because you're convinced that your raid as a whole will have a harder time, you're making a mistake."
