I think it would be a good idea for us (the WoW community) to discuss what things we liked or disliked about the quest in a constructive manner (keyword: constructive). This discussion could help shape how legendary items are handed out in the next expansion. MoP is close enough to done now that we can make judgements on the quest chain because it's mostly complete.
I'll kick off by quoting myself from the other thread on a few things I think the quest line did poorly:
Step 1, you can't have every other quest in the chain be "fetch me X dongles from raid Y". That is clearly designed to make it take longer, and it adds nothing to the experience. The latest in the MoP chain is the most egregious. You fetch Wrathion some dongles from ToT, and he turns around and tells you to go back to the SAME raid to fetch MORE dongles. My Jaw hit the floor when that happened. It ground the narrative to a complete halt and made both the new quest and the previous quest seem pointless.
Step 2, you can't make the quests dependent on RNG if they span the whole expansion (this is a follow on to step 1). There are plenty of ways to space out how long it takes to get each segment of quest done. You don't have to fall back on RNG that can be overcome in a highly variable length of time. This doesn't make the quest feel epic. It either makes it feel inconsequential (if you're lucky) or soul-crushingly tedious (if you're unlucky).
Step 3, if we have to fetch some dongles, make them special snowflake dongles. Every dongle must be different and have a place in the narrative. Tell us why this dongle is so important. Tell us why the big bad carries it around like a lucky charm (cause we're always after 'em). Tell us what this dongle will be used for. Some of the dongles in Wrathion's quests do work like this; the chimera of fear was a good use of dongle. The titan runestones were a BAD use of dongles.
Step 4, make sure the narrative of the quests has a well crafted tempo and flow. Random drop dongles take away the ability to carefully control the tempo and flow of these quests; DON'T use that technique. You need to be able to control the flow of the quest to make it feel epic and to prevent it from bogging down and becoming boring.
Step 5, for the love of the light, implement a catch up mechanism for alts. Wrathion's chain has destroyed my desire to gear my alts up for raiding. They force you to run old raids in LFR over and over to get the random drop dongles you need. This is bad. Instead, you could make the quests gated the way raid wings in LFR are gated. This means by the time alts come on the scene, all the artificial gating is already gone. The gating also lets you control the tempo at which the quests are completed in a way that doesn't require RNG.
Now for a few things i think they did well:
I think the quest chain spanning the whole expansion was a good idea. It lets them tie the creation of this item to the narrative of the entire expansion, not just the narrative of a single raid; this makes the legendary item more meaningful to that expansion's setting.
I like that the quest is available to all classes. This helps get around the balance distorting power of legendary items. The devs can balance around the assumption that anyone can get these goodies not just a single class. I know some folks feel this "cheapens" them, but I think the pros outweigh the cons on this.
Now it's your turn. What did you like the least about this chain? Why? How could it have been better? What did you like the most (and why)?
Remember, trying to articulate why you felt a certain way about an element of the quest will help the devs craft a better experience next time around. You can also try to come up with suggestions for improvement for them to think about. Also, stay constructive; we provide better feedback when the devs don't have to wade through waist high muck to trawl for gems (the technical term is "signal to noise ratio").
Thanks for reading my wall of text, and I hope this sparks some thought provoking conversations (hopefully more of the thoughtful part not so much the provoking part).