That's got to be some kind of first.
OP: If you're talking about people like me, we never wanted endgame in particular. We wanted a power plateau. The power plateau has absolutely nothing at all to do with an end game. Saying that a power plateau is like endgame is like saying all of a Grand Theft Auto game from the moment you turn it on is endgame, when it clearly isn't.
We don't want a game where the outcome is constantly decided by stats, and where you win or lose because of your numbers, rather than because of your skill. That leads to a game where you grind for gear in order to win, because bigger numbers equal victory. What that means is that you're grinding for victory; Which is more commonly known as time > skill.
It gets exceedingly tiresome reading the same old "slippery slope" crying over and over again on the forums. It is not, and I cannot state this firmly enough, a valid logical progression. In order for the slippery slope fallacy to be true, you need to factually establish that each event does, indeed, lead to the proceeding event, ending eventually at your projected outcome. Since none of the events leading to massive gear power differentials are present nor in the works, you cannot say that adding ascended gear/legendary gear leads to the aforementioned power differential. In other words, there is absolutely no evidence pointing towards a traditional MMO gear creep system. All anyone has offered are prophetic predictions of "just you wait, I'm going to be right and everyone will be sorry!" Until there is more concrete evidence pointing towards gear creep (say, for instance, markedly more powerful gear, that takes a substantially longer time investment, than the legendary tier), no one can accurately predict the outcome. So, stop bleating on about the slippery slope because you look like a whinging infant.
At any rate, let's have a look at the gear situation objectively. Firstly, ANet implemented legendary weapons. They're technically a tier ahead of exotic weaponry in the current hierarchy and, therefore, would logically be more powerful. Now, apply that to armor. If legendary weapons exist, then is it not logical to assume legendary armor should/will exist, too? Furthermore, you've probably noticed the time-investment and (in the future) power jump between exotic and legendary gear. It would be handy if the differential was lessened, so as to preserve the small power jump between tiers. Wait a moment, isn't that what ascended gear is meant to do? I do believe it is. Since they're incrementally adding the mechanics to obtain ascended tier gear, the only place to obtain it is via the forge or from Fractals (which my guild affectionately calls CITIZENS). It is of the utmost importance to understand that this gear will be obtainable from other means. Once again, we do not know the difficulty/time investment of these methods yet, so we cannot speculate with any accuracy the results.
Finally, I'd like to ask you what exactly would ascended gear impact? Surely not general PvE. Your ability to tag event mobs isn't inhibited by your gear. I would know because I levelled a char from 60-80 via Plinx runs. Furthermore, its impact on W3 is minimal at best. Especially considering the focus on larger confrontations. Sure, individual fights do occur, and often, at that, but you're not going to all of a sudden start losing supply camps/towers/keeps because a zerg of better geared players showed up. There are no resists in this game and players are all scaled to 80 in W3, so please point out where your performance would be detrimentally impacted by a 2% stat increase. Finally, ascended gear has absolutely no impact on s/tPvP.
ANYWAYS, on to the topic at hand. I do believe there is an active and healthy endgame. The difficulty is pinpointing where exactly this lies, as it is unique to each and every player. I, personally, spread my endgame activities between Dungeons, s/tPvP, and W3. I do not think there is a lack of content, just a myopic appreciation and exploitation of the game's mechanics. At some point, I think people have to realize that maybe GW2 isn't for them. I've had multiple guildies return to Aion because they didn't enjoy the fact that they couldn't sit in an area and endlessly grind mobs to level efficiently. At the time I was quite frankly blown away, but if all you've played are Korean MMO Grindfests, then that is what you enjoy. GW2 is not this. I also think people are grossly understating the potential of Dungeons. GW1 had a very, very competitive and healthy speed clearing community. Admittedly, the rewards from the areas you typically farmed were rarer than those found in GW2s dungeons. However, it would be nice to see a return of this sort of mentality. The sheer number of build combinations that GW2 offers lends itself very well to theorycrafting, something which really shines when you wish to complete an area in the most expedient and efficient manner. It may not be everyone's cup of tea, but I think it's an important alternative that not many people have looked into yet.
TL;DR: I'd encourage you to read my post, if only to help create a healthy debate, but here's the shortened version anyways. The Slippery Slope is a fallacy. It is completely and utterly incorrect due to the absolute lack of evidence behind the arguments. Ascended gear is meant to bridge the gap between current exotic and current/future legendary gear. No more, no less. Lastly, there is a healthy endgame present, but it's up to each person to find what it is for them.