This always happens on the sequel or expansion of any loved product, the inevitable bad review claiming how a product had ruined the franchise. I won't go to the extent of claiming that the entire Warcraft franchise has been ruined by WoW:Cataclysm, but at very least there's no foreseeable future for expansions if they are to keep to what they promised.
This damning promise is the dynamic world that was either promised or hinted at for its teaser, and how theoretically unfulfillable it is. Personally, I'd like to think that by this time Blizzard has developed a world editor program that allows them to make NPCs and items by selecting a model and skin from a customizable gallery and adding stats and text, and quests would be as easy as typing in a few paragraphs of dialogue, set completion conditions, and finish off with rewards.
With the entire face of the WoW game-world changing every few major updates, there's nowhere to go in promise for a new expansion, and with the lore severely limiting any new expansion bosses, but that was eventual.
From a dynamic world, there's only one more place to go in a game world that lets you fly anywhere in its established world, and that's space. To quote the great game reviewer, Yahtzee, once you go into space, anything else seems like a step back, which would be the game equivalent of calling the next WoW expansion "The Final Chapter."
In addition to the many lore faults inherent in making an MMO with a large writing staff working off of four games with two expansions and dozens of series worth of books, and decisions set out to please a fraction of the demographic instead of staying true to form leaving a bittersweet taste of acceptable constant canon instead of pleasing one fraction and annoying or drawing ire from another.
Personally, I'd like to see the Warcraft series try something other than the MMO genre, whether it be to going back to their RTS roots or more preferably going into more console friendly genres, like an Action-RPG or Sandbox game, or better yet, an amalgam of the two with PSN and XBL network play features. The way that Blizzard runs the important events anymore, it's not the players who do the important things anymore, it's their title NPCs. What better way to showcase their main heroes doing important things in their universe than a third-person action game where the players team up as, for example (player selected) Thrall, Chromie, Tirion and Ysera taking out Ragnaros, instead of a 10, 25, or 40 man raid of nobodies doing an intensive fight so that the Cenarion Circle can swoop in save the day and take all of the credit, if the players can fight hard enough to earn the cut-scene where they lose.
I'm rather sure that Blizzard was aware of all of this when they decided to start Project Titan, so they could start a new MMO fresh and without all of the adaptation problems that WoW has faced. Though they specifically stated that Project Titan was not supposed to be their replacement for WoW, that's more words to their inverters, Activision, and diehard fans than it is to their mainstream crowd. Besides, even if it's the final chapter in the MMO incarnation of Warcraft, if they were to admit that, then said diehard fans would stop playing Warcraft, thinking that their efforts will eventually mean nothing, investers would see it as a doomed project and pull out, and Activision might start interfering with their work, and put more chefs in their kitchen, (apologies for the tangential idiom.)
To conclude, I'll only say that I excluded going into specifics on this to avoid drama about what is or isn't in canon or a poor plot decision, and for, whether or not you'll believe me on this, brevity.