To this point, Mists of Pandaria has seen the smallest number of gearing dungeons in the game's history. This isn't about a lack of content, as there's more than enough of that in general, but the five-man dungeon has fulfilled a number of traditional roles in its history and I feel it's to the detriment of the game that it's taken a back seat.
The biggest issue, in my opinion, is the loss of the catch up mechanic in the progression curve. You've made recruiting extremely painful in this expansion for guilds stuck on normal mode encounters, and we who beg simply cannot choose. My guild already houses a couple of people who would be willing to make way for new players and play different classes, but it's already too demanding on our time to catch up our characters that have already done some raiding, never mind those that haven't.
LFR, as the sole catch up, is not a solution.
Previously, the system was different and it was the five-man dungeon that helped us along. From the inception of the idea during 3.2, we've seen the game move along nicely with the Icecrown trio, the revamped Zandalari dungeons and Dragon Soul. These allowed players to plough as much time as they deemed necessary into gearing up an alt so that they could help their guilds, play different classes, and generally be more flexible to their community.
Now, I understand the issue: the problem with the previous incarnation of this catch up system, the one we saw in Dragon Soul, had the rather unfortunate side effect of making the previous raiding tier absolutely redundant. We live in a world where content is coming out faster than ever, and I'm not sure that the developers could keep up with the demand even now if they were to allow people to wholeheartedly skip tiers as they did then.
But the dungeon system needed a tweak, it didn't need jettisoned entirely.
The Zandalari dungeons were a good example of how this can be done. They came between two major raiding tiers, but were set at an item level that didn't make the previous tier redundant. They were good for the hump and allowed alts to get themselves ready at a more reasonable rate than today, without necessarily ruining the tier of content that came before them. To paint this example more accurately, if the Dragon Soul dungeons released gear that was item level 372 rather than 378, the catch up would still be available but Firelands would still be worth running in order to get the better options that still resided there.
Please, do not talk to me of heroic scenarios. I know what they're going to do, I know what they're being designed for, and I'm sure they'll be fun in and of themselves. But expecting people to try and catch up by hoping that a single drop might have something they're looking for is going to lead to even more frustration than the silly system we have now.
The ship for 5.3 has sailed, and that's fine. But for 5.4 and the Siege of Orgrimmar, I don't see why three dungeons can't be pulled in to provide a better catch up mechanic than what we have. Ragefire Chasm can be one, and its contents need little more than retuning. Other dungeons from the classic era such as Blackrock Depths or Razorfen Downs could be given heroic modes so that players don't have to put up with the cesspit of LFR, valor and daily grinding just to get themselves ready for a new tier of content. An item level of 512 to 516 would be just fine and wouldn't cause the Throne of Thunder to be skipped entirely.
Before closing, I'm going to appeal to the heart.
It was Blizzard that gave casual players the opportunity to participate in the game's best content in WotLK, and get involved in "progression". In Cataclysm, brutally punishing content took that opportunity away to an extent, but at least there was dungeons to let players catch up. Now, not only is the content too punitive on normal mode, there is no viable catch up mechanic outside the ghetto of LFR and the meandering hope that what you need might drop.
Come on, Blizzard. There is more to your community than the hardcore or the mega-casual. It's time to start thinking about them, too.