People need to understand the difference between a "failure" and a "disappointment".

A failure means something didn't accomplish it's goal in any way whatsoever. This is what you're trying to say OP, and that I disagree with. Heavensward didn't "fail". It's still holding enough subs to keep the game going, which is pretty much the end all goal for SE with this game. Whether we like the game or not doesn't change the fact whether it is or isn't a commercial success. The word you're looking for is something akin to a "disappointment" which is something that I can actually agree with you about. The game didn't change the formula, and it seems we're going to be getting the same thing in 4.0 which annoys me greatly.

So yeah, HW didn't fail. It just didn't impress you(and many of us). As long as it doesn't fail, we're going to be seeing the same things for the next few years. And that bothers me a lot.