To start this off what I don't want to see or hear about are any things that have no direct correlation to social interaction, i.e. class changes, transmog and etc.
There are about as many opinions on why WoW is declining as there are suns in the universe! For me though, the loss of social interaction is really making the game unplayable. When I look back at the old days before any LFG was installed, you had to be sociable to complete anything that you couldn't solo. Meaning you were in trade chat looking for some players to help or in the lfg channel. You had to interact with players before during and most of the time after the dungeon or raid or even quest was complete. With the ability to just que up and run through anything with players you don't know, probably wont talk to at all unless they are messing up, and mostly will never play with again, takes all the fun out of running anything to me.
I know most of you are going to say but you can join a guild and this and that, but even joining a guild doesn't mean that you wont be needing players to do a 5 man heroic or 10 man raid. The fact is that unless you have a certain ilvl with a certain achievement you aren't going to be doing anything at endgame except for the unsociable LFD and LFR and that is in a sad place regardless of what anyone thinks, item level will never out way skill, except it does now.
Anyway enough of me crying about not having any friends, I would love to hear from players who miss the social interactions and your opinions on the state of play.