As long as they focus on lore and present it well. I couldn't care less about doing stuff with barrels in that green jade village or whatever...
Now you see it. Now you don't.
Heck, we had the battle for Undercity (which was almost like a scenario) that crowned the Wrathgate questline perfectly. And no one called it wasted development time.
Essentially this is what happened/is happening with scenarios;
Scenarios revealed: Cool, short, story driven instances where you can queue instantly without regard for tanks or healers.
What actually happened: Short instances with instant queues, no good delivery on any story elements and no gear.
What happened in 5.1: Good, story related instant queues that give valor.
Now, between launch and 5.1, Blizzard has apparently realized that people WANT story in their scenarios. This seems like a no brainer given that they were initially advertised as being just that; short instances that progressed the Horde/Alliance war across Azeroth. *That* has only just started in them, but what we have is pretty good. Far greater than the first batch of scenarios was. Plus, they do still give valor.
Wasted dev time? I wouldn't say that. Even the launch set serves the purpose of getting players points. However, I do openly admit that I *wanted* story in them from the start. However, MMO development is very much an organic, living process. They will NEVER score a homerun on every single feature added from day 1.
They aren't a waste of development time, but they should be a bit more rewarding.
I don't know if this was covered in 10 pages, but I feel a lot of people are still unaware that you can queue for LFR, Scenarios and Dungeons simultaneously. This is fairly awesome when damage queues for lfr are 30-45 minutes and Heroics are ~15.
I personally feel running them the initial time was fun. You had some lore explained to you and the gameplay inside wasn't too bad. Their replayability simply isn't there for me though, as there is no meaningful reward that makes me want to do them more often, like with 5 mans and valor/justice points, or even to do them on different characters when I've leveled them up.
I would like to see them expand on the idea and allow a different type of scenario that gets more and more difficult as you complete it for the first time. You do it once, you get to "level 2" difficulty (or whatever you want to call it) then you run it again, complete it, and get to "level 3" difficulty. At each milestone; say every 5th level, an additional reward is added to the bag at the end of the run. For every 10th level, the quality of the reward for one of the items increases also.
You will have, in essence, a 3 man dungeon that doesn't rely on the trinity of tank/healer/dps. You could even have lore items as a reward in the bag at higher difficulty levels. Vanity stuff, transmog stuff; things of that nature.
It's always been Wankershim!