Looking at Cataclysm from a purely story perspective, it lacked major elements that are nearly universal in storytelling.
There was no build up to the Cataclysm. Obviously, in-game there were some events prior to it, but those were minor and in the scope of the story were not sufficient. A build-up of tension or early introduction of the plot is absolutely necessary. This simply wasn't there. We beat Arthas, and then we wait for like a year. And then we're told to buy the fact that some guy that most of us don't even know just reshaped the world overnight. Whereas with Arthas, everyone knew who he was. You had multiple zones, even dungeons, with references to him. Even when I first started playing about 5 years ago in early BC, within a month I already knew about the Lich King and that he was bad. In those 5 years, the only references I ever heard of Deathwing were vague and generally through outside sources.
Another huge narrative misstep was Firelands. Again, remember, I'm addressing it merely from a story perspective. Firelands was simply a repeat of the Molten Core story that was resolved years ago. We're given one zone at the beginning of the expansion to sell us a story we've already resolved. Druids of the Flame were vaguely hinted at over the years, but again, they were just kind of thrown at us and told to buy it. Suspension of disbelief overload.
Finally, most of Cataclysm content had only a few references to Deathwing. Yes, I know there are *some* quests that Deathwing is a major part, but unless you're going out of your way to complete entire zones then you will most likely miss the references. This means that by the time Dragon Soul came out, Deathwing has still not been properly built-up and we're left with a climax that simply fizzles. Compare this to Wrath of the Lich King where you are introduced to the final villian at the door and every step along the way. The only zone that I can't recall a major Lich King presence is Grizzly Hills, but by the time you've reached there you've covered nearly all of the Fjord or Borean, and even possibly Dragonblight. All of which are zones you can't ignore the Lich King's presence.
The very first dungeon of WOTLK introduces you to LK with direct references including the end where you see a Valkyr turn the boss into an undead. BRC on the other hand falls short. Of course, Twilight Cultist are linked to Deathwing, but I don't know anywhere in the dungeon where you're directly referenced. Unless you know the lore, its easy to complete BRC without knowing it has any relation to Deathwing.
Prior to Cataclysm there are absolutely 0 dungeons with any direct reference to Deathwing, and as far as I can tell, with maybe the exception of Blackwing's Lair, there are no hints to him.
Compare this to 6 zones (Tirisfal Glades, Silverpine Forest, Western Plaguelands, Eastern Plaguelands, Eversong Woods, Ghostlands), 3 races (Forsaken, Humans, and Blood Elfs), 3 instances (Razorfen Downs, Scholomance, Stratholme), 1 raid (60 Naxxaramas), 3 factions (Argent Dawn, Scarlet Crusade, Brotherhood of Light), all with major references prior to LK release.
After release you have Utgarde Keep, Utgarde Pinnacle, Drak'Tharon Keep, Old Kingdom, Azjol-Nerub, Trial of the Champion, all with direct links to the Lich King. You have two factions directly linked to the storyline (Ebon Blade, Argent Crusade). Two raids prior to the final raid (Naxxaramas, Trial of the Crusader). And all but two zones (Storm Peaks and Grizzly Hills) with unignorable quest lines.
Compare this to Cataclysm where we're thrown this story at start up and asked to buy it. None of the five mans directly involve Deathwing (sans Hour of Twilight, but notice I excluded the Frozen Throne for the purposes of these comparisons as well.) There are numerous references in zones AFTER the fact, but many of those references take a lot of digging to find. Only one faction (Earthen Ring). And the result is an underwhelming interest and understanding in the story.
These are all BAD things. If your audience is confused and not excited, they become distracted and you'll lose their attention. Apart from any game play issues, that's exactly what happened.
Hour of Twilight was way, way, way too late and should have been released when the Troll Heroics were. Really, they are the first real explanation as to what is going on and who Deathwing is. By the time we're given these revelations we're just fed up with the story.
Edited, May 2nd 2012 4:05am by ekaterinodar