The news that Blizzard is going to stop putting out new 5-man instances for Mists seems to have caused a bit of a stir.
Those people who gear up using LFR kind of shrugged and said "no big deal". So did those who like the new Scenario concept. And the "I love dailies" crowd chuckled and continued muttering to themselves in a corner.
But for me, I see this as the continuation of what started in Cataclysm.
Cataclysm began the deviation from the standard Warcraft pattern by instituting Heroic-only 5-mans, and then segregated them further by separating them out in the LFG queue. I can presume this was done so that those who wanted to either gear up to the latest tier or max their VP acquisition could do so in the most efficient manner, but as in all things there were unintended consequences.
By subdividing 5-mans like that, the queue times soared to levels only previously seen in obsolete 5-man end game instances.* Starting with the Zuls --Zul'Aman and Zul'Gurub-- people began to complain about a lack of variety in their instance runs. Finally, the new Heroics created an "asshat divide" within 5-mans: asshats flooded the 5-man Heroics, particularly the latest ones, while people who simply enjoyed running instances gravitated toward the baseline 5-man Normal instances.
However, those who enjoyed 5-man Normals found their options sadly lacking as compared to their Heroic brethren. Unlike Wrath, which had the same number of Normal 5-mans as their Heroic version --16, if you were curious-- there were only 7 Normals vs. 14 Heroics in Cataclysm.** Perhaps the statistical data for Wrath showed that not a lot of people ran the ICC Normals, but instead of making the last patch's instances Heroic-only, Blizz took their solution a step further in Cata and eliminated the Normal option entirely from all major patch instances. It wouldn't be so drastic a step if it weren't that Cata dropped with only 7 Normal instances as opposed to 12 in Wrath.
And now we come to Mists.
Mists shipped with 4 Normal 5-mans (9 Heroic), and that's going to be it. If you're an instance runner, you're out of luck.
While Blizzard will point out the Scenario model that is new to Mists, they are all tuned for max level and are designed for a "dungeon-lite" experience. I look on them as the equivalent of a multi-player Daily that you can queue for, not a traditional instanced dungeon.
So what happened to the slate of instances we are used to seeing in an expac?
Blizzard has decided to use LFR for mid-expac progression, and as a consequence instances have drawn the short end of the stick. To be fair there were only 4 new instances post-release in Wrath versus 5 in Cataclysm, but those 4 represented only 25% of the overall total of Wrath instances as opposed to 36% in Cata. Think about it: Wrath shipped with 12 instances, while Cata had 9 (7 normal). If you look at Normal instances alone, this is a further erosion from the Wrath model: 12 -> 7 -> 4.
If you only ran Normals, Blizzard didn't design any new instances for you at all once Cataclysm dropped, so this erosion isn't new behavior to you. What is new, however, are how few Normal instances are now available and the lack of future prospects for those instances.
As much as Dave Kosak Twittered that there will be more 5-mans in future expacs, the numbers don't lie. Instances are less important to Blizzard moving forward. Scenarios and LFR will get the development time previously allocated to instances, and the expectation is that you will use instances to assist you in getting that initial "raid ready", but instances as a viable max level activity will be phased out.
Before someone says that Blizzard is swimming in money given the number of subs that WoW has, remember that profit doesn't translate into more development staff. Even if there were more development staff around, items such as Pet Battles have taken up significant development time, further eroding the time to devote to 5-man instances.
Finally, let's not forget the elephant in the room: Titan. It could also be that Blizzard is shifting priorities to their next gen MMO. Any low hanging fruit, such as instance development, will get put on the back burner.
I think we can safely say that the BC/Wrath era of instances is now over. I'll miss having a lot of instances to run, as my limited playing time prohibits even LFR from being an option, and Scenarios are of little use to someone still leveling a toon in Pandaria. But I also thought it a mistake by Blizzard in Cataclysm to not pair up Normal instances with the latter Heroics, as those Normals became a refuge from the drama that so often infected Cata Heroics.
But hey, popularity doesn't lie, right?
*I once waited 2 hours for the queue to pop for a 5-man Heroic Tempest Keep/MgT run back in Cata. Amazing how much farming you can get done in that time.
**Since BC instituted the Heroic we can't count Vanilla, but in BC there were 16 instances and all had Normal and Heroic settings.