There is one thing

In apparent contradiction, however, if you offered me an MMO that forwent the levelling experience, one that said, ‘Bing! You are max level from day dot — go forth and raid’ I probably wouldn’t be able to enjoy that either.
It’s possible this contradiction arises from one of the inner-shifts as a gamer I’ve gone through over the years, where the value judgement I make against the components of an MMO hasn’t kept up with what I might actually enjoy.
I think the reason I wouldn’t accept (at first?) an MMO where you could go do everything from the moment you logged in is that it would feel undeserved. Unearned. Cheapened by not having ‘suffered’ to get there. That means I believe at some level that access to raiding and the end-game gear experience is something that must be earned in the first place.
Wait, do I Believe That?
When I take it out into the light and say it plain like that, I’m not sure that IS something I believe. Or at least, it isn’t a standard I would enforce on anyone else. But does that then follow that I also believe I’m on some other level — higher or lower — than my fellow players?
I don’t think so… Not now at least. Not consciously. I do wonder if there is an implicit bias1 at play. Something that may have roots back to when I was more firmly entrenched in the PvP player base.
While I never bought into the hate that existed between the PvP and PvE groups, it was pervasive. It was impossible not to feel immersed in it, the feelings ranging from pity for the poor lambs who didn’t understand, to disdain, to outright and open hostility.
I generally took the tack of trying to convince and sell people on the benefits (as I saw them) of the PvP way of life. I simply exited any conversation it was clear this simply was not going to happen (aka, most of them).
There were a number of motivations for the tack I took, many altruistic, but some as a matter of preservation. I think a large part of the hostility that existed between the two groups stemmed from a vocal outcry against implementation of any kind of meaningful PvP in new MMOs from the PvE sphere. It felt like being under near constant attack and having to defend the style of play we enjoyed best.
More than likely that was a belief shaping experience.
My Recent Experimentation
Enter The Elder Scrolls Online and more recently, Final Fantasy XIV.

A lot of what I just wrote for the prior section I thought through as I wrote it. But even before, without that level of introspection, I had a vague desire to try ‘learn’ how to better enjoy an MMO more completely.
What ESO and FFXIV have in common which made them good candidates in my mind, was a stronger focus on story than most of their competitors. While I’m far and away from being in a position to judge their overall quality in this regard, I’m enjoying what I’ve seen of both so far.
FFXIV previously allowed itself to get too bogged down in requirements to do some fairly bog-standard MMO fetch and kill side-quests. Now the XP-tuning so far seems to allow you to bee-line the MSQ (Main Story Quest) which makes it much more likely I’ll manage to get through it.
Part of the mindset shift I’m attempting is to mentally treat these two titles as the co-op/multiplayer Elder Scrolls/Final Fantasy titles I always wanted and simply put aside the fact that they’re MMOs — and all the baggage those come with.
While it’s still fairly early on in the experiment, it seems to be working. I haven’t even been tempted to look into what the raid-metas might look like, the health of the end-game scene in general or anything else of that nature for either title.
No doubt I’ll engage in the endgame if and when I get there, but that will come after I’ve stopped to smell the roses along the way.
I enjoy leveling more than end-game for the most part, but the pressure to get to the end where all the other players are can be a real downer. The two games you mention do a good job actually of keeping players engaged with earlier zones/content so at least you’re not leveling through an abandoned wasteland for most of the time. I’ve had very mixed experiences with instant ding leveling, it normally leaves me quickly disengaged with the character or game, I can only think of one example where it did stick – my Shadowknight in EQ2, but he dinged to a relatively low level and I’ve played him through several expansions since so had plenty of time to get used to him.
I don’t know if I’ll ever get to a spot where I enjoy the leveling process MORE than endgame, although never say never, I guess. :)
And you’re right about the games keeping people in the low level zones, in both games I’ve seen them be fairly well populated. FFXIV in particular actually which really surprised me. I guess people are coming back even to the lowbie zones for alt-job leveling?
I didn’t mention in my post, but I don’t really have anything against boosts in principle when it’s content I’ve already played through. I’ve had the odd boost from WoW (mostly just ones included with xpacs) and I quite appreciate skipping the content I’ve done over and over and over. xD
I can stay engaged with those OK, but I’d still feel uneasy and likely, like you, disengaged if it was skipping ‘new’ (to me) stuff.