I get your point... I'm just not interested in a D&D that has no alignment in it (even if it has to be an optional module). I enjoy the Moorcockian feel that alignment brings to my D&D games, where alignment isn't necessarily about describing your personality (though it can and often times does paint a broad picture of it), but is instead about aligning one's self with a cosmic force and promoting that cosmic force either explicitly or implicitly through one's actions and deeds.
Well, if you like it, there's an end. There's no disputing matters of taste. (Because mine is obviously right and yours is obviously wrong, of course!

I hope you don't mind if I ask you a few questions about how you do this, though?
Because while I'll grant you that the term 'alignment' does seem to suggest some sort of interface with cosmic entities, this doesn't really seem to be manifested in the rules very much. How does it appear at your table?
If a Lawful character has some sort of explicit allegiance to cosmic forces of Order, sure, I see that that makes a difference. But of course most Lawful characters do not - and you allow for this when you say that one can implicitly promote a cosmic force through one's actions and deeds. Let's look at that implicit case.
What difference does it make to gameplay? How does this implicit allegiance change how the character is played, or how the rules treat that character? (Aside from things like 3e-style 'Detect Law' spells, that's obvious. Such spells of course did not exist before 3e.)
(I have serious difficulty comprehending what a cosmic force of Order would even be like, I have to confess. There is no one ultimate Order, there are different orders that are mutually incompatible. And I have even more serious philosophical objections to a cosmic force of Evil that people bear allegiance to. In my view, even demons and devils don't give a fig about Evil with a capital E. They corrupt souls because they get status, power, and/or pleasure from it; they engage in destruction because they find it fun. If they did those things out of disinterested pursuit of Evil (TM), one could argue that it would be a step toward goodness!)
I think that is our disconnect, I don't expect alignment to tell me all the facets of a person's
I never claimed it was supposed to tell you all the facets of someone's personality. I in fact say that it tells me just about nothing about their personality. It has no effect on how I play the character, either as a player or as a GM.
I have no problem with them being "ill-defined" since I think what they mean are going to vary slightly from campaign to campaign and DM to DM.
By "ill-defined", I don't mean 'vague' or 'unfocussed', I mean, 'incoherent and inconsistent with itself'.
To take what I find the most egregious example, Chaos is somehow supposed to be both 'randomness' and 'love of liberty'. Those two things have nothing to do with each other! And the effort to force them to lie down together leads to mental contortions that I find quite unnecessary.
Since (so far as I can see) Law and Chaos are grab-bags of incompatible ideas, people seize on one and emphasize it the most... or different ones in different situations. And when someone else comes along and emphasizes a different one, trouble ensues.
As an example... in the Young Kingdoms good and evil are vague and barely recognized concepts by most (it's the fact that Elric feels any type of "moral" quandaries that sets him apart from his people),
You have ably illustrated one reason why I find reading those books to be an exercise in masochism. They are about an unbelievable society of sociopaths, utterly lacking in sympathetic characters. I can't think a human society where good and evil aren't live categories. I might think a fictional culture is mistaken about good and evil, they might think some things good and evil that I can't understand the rationale of, but a culture that just doesn't care? They come off as sock-puppets rather than people.
Now, I willingly grant that it's been decades since I read the books, since I don't like them. But what do Elric's moral qualms come to ultimately? Do they ever, in fact, guide his actions? Let's remember we're talking about a guy who routinely sucks people's souls into his sword to preserve his own skin.
Even Arioch, a supposed Lord of Chaos, doesn't come off as very 'chaotic' to me. As far as I can recall, he's just straight-up evil.