All sounds good, and I'm glad too that GURPS doesn't try to simulate each of those factors with every blow. (Though I wouldn't heap any special praise on the game for that; I'm not aware of an RPG that does fuss over the many ways to miss.)

Anyway, I also like the idea of not worrying about all that! Easiest to just not think about the details of a 'miss'.

But if we do consider the technicalities of a 'miss'... hmm, thinking it over, I have to say that in the end, I don't care to assume that one of a half-dozen inerpretations of 'miss' may have taken place. I prefer a really simple stance of "You hit or you flat-out miss; at the level of detail we're playing, the game doesn't consider more nuanced ways to 'miss'".

The reason is that some of the ways to 'miss' will conflict with other rules. Or, some of the ways to 'miss' are, IMO, already covered by other rules. Or some of the ways to 'miss' are just more detailed variants of the simple flat-out miss (in which case the description is fine!).

Let me take your list (which is good and interesting stuff!) and peer closely:

• Hesitation: Per the article, hesitating vs flat-out missing has real game effects. If hesitation describes some misses, then those misses shouldn't use ammo, make a weapon unready, allow counter-actions that depend on an attack having been made, etc.
• No opening: No "opening" assumes an actively defending opponent, which isn't always the case. And if one halts an attack because there was no opening, the same notes on hesitation above apply. (IMO, taking the Evaluate action already does an okay job of simulating waiting for an opening, especially Evaluate followed by Deceptive Attack.)
• Missing the target: No problem there! It's what I (and default rules, I assume) assume a miss to be unless indicated otherwise.
• Not right distance: Hmm, if you're too far away and miss because of that, I'd say that fits under a regular, flat-out miss (above); the little extra description is nice. On the other hand, if you're too far away and thus don't attack until you're better within range, I guess the rules equivalent would be actually taking Move (if the distance factor is a matter of whole hexes), or Evaluate (if you're technically the right distance on the game board, but want to simulate that real-life matter of getting the inches just right).
• Foe avoids blow: Scoring a "hit", which the foe then dodges, is the clear way to game this; no problem there. I believe you're talking about a TH 'miss', though, which would have been a hit, had not the foe moved in some minor way (not big enough to burn an active defense). Maybe that can simply fall under the category of not getting the TH bonus for a stationary target; either way, it seems a flat-out miss with a little added description, and I don't see any conflicts with other rules. Looks OK!
• Not counterattacking: Looks similar to hesitation or "no opening". Again, I'll note the same rules conflicts as hesitation carries, as well as note that taking Evaluate simulates this fine, IMO.

The point: I like the list, and fully support creative description of actions like that! But I personally like to limit the creative description to things that won't conflict with other rules.

"You struck from a little too far, and fell inches short of the target." No conflict with regular 'miss' mechanics there; sounds good!

"Okay, you've done Evaluate for two turns, and now take Deceptive Attack at -2 TH, -1 AD... You hit! You watched and really picked out an opening in his defenses." That sounds nice too; no conflicts that I see.

But: "You miss... Let's rule that you didn't find an opening, and didn't attack..." That just raises questions: "Opening? But he just did AOA; his defense should all be open!... And if I didn't attack, why can't my axe Parry now?... And if I didn't attack, why am I now vulnerable to his Riposte?..." And so on.

If there's conflict like the above, I'd prefer to either:

a) apply the description to other circumstances that don't conflict. (Example: Use the description of "you wait until you find an opening" for the Evaluate action); or

b) abandon the description, placing it on the infinite list of details that the simulation just doesn't support. (Example: Admit that the basic rules don't cover involuntary "you do nothing at all" hesitation; we should leave it out, or add it in if we want, with any required considerations so it matches the mechanics of "no attack".)

That makes things cleaner in the end, IMO – and there's still lots and lots of creative description, such as much of your list, that does play nicely with existing rules.

(I'm waxing a bit philosophic, as it's all one of those "principle of the thing" matters anyway. If you do allow, for example, the "hesitation" description, and selectively apply it only when there aren't any polearms or bullets or Ripostes or other conflicting rules in play, I think we agree that nothing's going to explode, and probably no players will even think to complain!)

Thanks for the interesting food for thought!