The question is, now that they scarified [Ed: sacrificed?] dungeons, how long will they continue to make new raids during an expansion?
Scenarios are nothing else then PvE-battlegrounds. Will they continue to produce new raids or will they take the simple route there too and replace raids with bigger scenarios, with PvE-battlegrounds.
I think Blizzard will continue making raids. Specifically, Looking for Raid overlaps with dungeons. It's transient, formal Trinity group content. The ratio of tanks to dps is more likely to match what is played. Plus, raids are the expected method of increasing gear level. There's a pattern there, and the playerbase expects raids to be obsoleted as time goes.
Admittedly, there is a difference as dungeons are small group versus the large raid group. But I think that Blizzard is making an effort to include more small group options out in the regular world. It's probably a lot easier from an art creation perspective to throw a few elite mobs out there.
Plus, and I think this is very important, they get a 2-for-1 with the raid artwork. The same amount of artwork produces both transient group content and extended group content. So I think raiding still fits in the game where 5-man dungeons start getting squeezed out in later patches.
I may not have mentioned this before, but I think that art asset creation is the "blocker" in modern game development. The amount of new artwork an idea requires often determines whether or not it is actually implemented.
While I don't disagree with your assertion, and it makes logical sense, I throw in another suggestion:
Compared to the development work that goes into your typical dungeon (including the various difficulty levels), I imagine that Blizz could make a bunch of Scenarios for the same time, effort, and money it takes to make a single "second tier" dungeon.
Loot aside, what would you prefer? 2~3 new dungeons, or 5~10 new Scenarios?
Ah, but as above, I don't think they're funneling that effort into scenarios. Sure, they're making a couple new scenarios each patch. But I think the lion's share of art and content dev time is going into the new raids.
Look at this patch. We got a 13-boss tier following a 16-boss tier. Has Blizzard ever done two consecutive raid tiers with that many bosses? Especially in the given time frame?
I certainly would rather have another 15 or so raid bosses in 5.4 rather than a 6 boss raid and a couple 5-mans.