I went down a rabbit hole today, through Harbinger Zero and TAGN—twice—to Spinkville. This is the result:
I think current and future MMOs are caught in between a rock and a hard place. We all talk about the fact that success shouldn't be measured by anything other than profitability. Well, I do at least.
SWTOR isn't a complete success, therefore it is an abject failure in the eyes of many. Tons of people are still playing and enjoying the game. Count me among them. On the other hand, I haven't raced to the top, still working to reach 50 on my main, and enjoying the journey. I am definitely an outlier there, I suppose. I also don't see an issue with replayability. At least eight(8) stories can be played through, with other ways besides the planet quests to help level outside the storyline; like space combat, PvP, Flashpoints, random murder. But cool, it's a failure.
Are people tired of WoW and WoW-clones? I don't know, ask the millions of people still subscribed to WoW and its clones. I guarantee only a minuscule fraction of them is even aware of this debate.
The problem new MMOs have is that they must compete with an almost 8 year old behemoth. Maybe the original game only expected 500k players and had only(!) a $63 million budget, but the three expansions since then have surely topped $200 million in investment, at the same time the game was enjoying unimaginable profits compared to everything else in the genre. What new game can possibly compete?
If you're using a shard system, some costs are scalable, but they're mostly related to hardware and customer service. The basic development of the game world and all the game content and features have to be fronted, and compete with WoW's 4+ current continents with all the different racial starting areas, and the dungeon finder, etc., that took Blizzard well over a decade (including initial development and the development of the expansions) to develop.
[EDIT] Understand, while I am a fan of WoW, I do not consider it the end-all-be-all of the MMORPG genre. The game has serious flaws, and I haven't played in over six months, haven't played hardcore in well over a year. It is, however, the unbelievably huge blockbuster every other MMO—and several SP games— is compared to.
Until the market splinters more fully, I don't see any developer action replacing the attempt to capture WoW's lightning-in-a-bottle again.