I've spent quite some time in WoW, had a blast with Lich King. Then Cataclysm came and I switched from PVE to PVP because I did not like the world changes at all, I even think that I leveled my char mainly in PVP to 85 at that time.
I switched to Defias Brotherhood, since on my old server I was at the end of the ladder of rated battlegrounds aaaaand did find a nice rp guild there, had an awesome time there, awesome rp events - basically rp players generated their own content.
Then Mists of Pandaria was released which I even liked less than Cataclysm, most of the people on Defias left WoW, server population dropped to half with the open world PVP changes - many rp players were open world pvpers.
The streamlining process changed the whole gameplay and mechanics of my class, so I said fuck it, I am out of here aswell.
Apart from that, the community changed a lot and I mean a lot with the Cataclysm expansion.
They should have put more of that into the game:
https://www.youtube.com/watch?v=Ch4rc5W4dKY edit:
Sigh, that was the rp guild, good times:
https://www.youtube.com/watch?v=E1MEkwobgI8 And that 6 hour fight in the tram between ironforge and stormwind on a saturday night, with varying numbers:
https://www.youtube.com/watch?v=uLEcQKUVjJE