There's enough solo play already in a game that's relevant content used to be team based only. Seeing everything in the game in one day since you can do it solo - that's the cancer that slowly nags away motivation and makes it hard to keep people playing nowadays. While I see where this is coming from - people being able to overgear ever more content ever earlier, mixed with rather hostile atmospheres in LFR / LFD, which are usually getting carried by ~20% of players in group - WoW's strength and catchphrase has always been to overcome obstacles that couldn't be taken on alone as a team. That's what the game is designed around, and this won't and shouldn't be changed. Sorry if that's not what you wanted - wrong game, door's over there.
Yeah I know there's DKs soloing MoP raids already - doesn't mean that this should be. If you ask me that doesn't make sense and should be taken care of. Other games do that just to make a point.