I was just thinking about this the other day, and I reflected on why WoW lacks excitement currently. Its not because the downtime between patch cycles, but it stems from a much greater problem than that.
WoW has become a bucket list. Now hear me out on this. The game is essentially played by creating a bucket list and following that list.
Goal: Cap valor asap and continue to do so on other characters
2) Daily Heroic Scenario
3) Daily Heroic Dungeon
4) Battlefield Barrens weekly
5) An LFR or two
6) Rinse and repeat.
Notice the only thing getting the player out in the world is the barrens weekly quest. Everything else is queued for. Its just not exciting. And after one week of the barrens quest, it gets old, especially when its done on other characters.
Where is the excitement of logging in, and then figuring out in game what you wanted to do for the day? There are no more goals that are actually worthy of time and effort other than heroic raiding, and even that becomes dull because you essentially fought the same boss with some ability bloat to create difficulty.
Now contrast that to an epic quest chain like the Onyxia quest line (for Alliance). There were several steps, and accomplishing each step just to gain access to that raid boss felt like you were gaining ground. You got gear along the way inevitably as you went through BRD and other dungeons. The player felt like a part of the quest. Or the quest chain that gave access to the Black Temple. Each step in the quest felt amazing because you saw how your accomplishments opened new parts of the game for you to explore. Now, the legendary quest chain is just another bucket list type quest chain. Its too carved out in stone, and feels generic.
WoW lacks excitement because the developers made the decision to create such a simple bucket list type system, with generic quests, and overly simple dungeon / raid design.
In other words, the game is great in the gameplay department, but lags behind in the excitement factor.