OK...
Sure it can. Your condition was clearly stated, but too complicated for contingency to carry out.
Right… “one magical atom.” I almost forgot.
The spell doesn’t know. That’s for the wizard to decide when he casts contingency. If the conditions are set to react to a physical blow (specifically a d20 roll that either does hp damage or is shrugged off by DR—the DM and player would have to come to an understanding about what a “physical blow” is), then a dragon’s breath or a lightning bolt would be ignored.
That’s true, but the fact that the range is personal and the target is “you” says a lot. The absence of any area of effect is also telling. The examples I gave help with filling in the gaps, and I might also add that a variety of Forgotten Realms novels, most-notably anything by Ed Greenwood, reinforce the examples found in the PHB and various other sources dating back over 10 years, two of which I already referenced.
How could I possibly assume that the examples given are the only possible examples? How could anyone assume that? I don’t mean to answer a question with a question (two questions, in fact), but seriously…
Come on, should I have started a new paragraph to explain this? I was loosely referencing the PHB quote that you should already be familiar with. Fine, how about “dunked” in water or “submerged” in water. Better?
Gust of wind doesn’t simulate a drop in altitude, and yes, one could state, “If I fall five feet or more, a feather fall is cast upon me.” That would work fine.
I think we can all agree that a successful attack means overcoming the target’s AC, coming into contact with the foe. The write-up dates back to 2E, so the wording might be different. Semantics is for another forum.
You’ll have to take that up with Azalin. I suppose being a lich, commoners won’t be able to get close enough to Azalin to cause him any harm, so his contingency is tailored to thwart those who can fight through the lich’s minions and actually get within range to attack.
No. Elminster’s Evasion does not protect Elminster from loss of mental faculties. It teleports him to his safehold after he’s lost them. It’s up to the DM what that means exactly (Int at 1? Unconscious? Dominated?), in the same way that it’s up to the DM to identify what “successful attack” means in Azalin's case.
This is a good example of a clearly-stated trigger that is too complicated for contingency to handle.
They cannot be both "clear" and "complicated/convoluted".
Sure it can. Your condition was clearly stated, but too complicated for contingency to carry out.
Tell me, how does the spell -- which only knows about the universe out to "one magical atom" away from the wizard's skin, remember -- distinguish between: an arrow and a dagger; a fireball and falling into the campfire; a meteor swarm and a handful of coals from a fire?
Right… “one magical atom.” I almost forgot.

Because no explicit limits are stated. Nothing in the spell description limits the condition to things the wizard him/herself directly feels, experiences, or is aware of.
That’s true, but the fact that the range is personal and the target is “you” says a lot. The absence of any area of effect is also telling. The examples I gave help with filling in the gaps, and I might also add that a variety of Forgotten Realms novels, most-notably anything by Ed Greenwood, reinforce the examples found in the PHB and various other sources dating back over 10 years, two of which I already referenced.
The fact that these are the examples does not mean that they are the only possible examples.
How could I possibly assume that the examples given are the only possible examples? How could anyone assume that? I don’t mean to answer a question with a question (two questions, in fact), but seriously…
And it distinguishes from a heavy rain (or a bath) how?
Come on, should I have started a new paragraph to explain this? I was loosely referencing the PHB quote that you should already be familiar with. Fine, how about “dunked” in water or “submerged” in water. Better?
Gust of Wind? Jumping off a 10' wall on a windy day?
Gust of wind doesn’t simulate a drop in altitude, and yes, one could state, “If I fall five feet or more, a feather fall is cast upon me.” That would work fine.
The condition states "is successfully attacked", not "takes damage", and the spell goes off as an Immediate Interrupt, which means the F-to-S takes effect before the attack is completed, nullifying it.
I think we can all agree that a successful attack means overcoming the target’s AC, coming into contact with the foe. The write-up dates back to 2E, so the wording might be different. Semantics is for another forum.
Because it burns the contingency even if it's a L0 Commoner stabbing you with a spork. There's no point in wasting the contingency on a situation where you are not actually threatened.
You’ll have to take that up with Azalin. I suppose being a lich, commoners won’t be able to get close enough to Azalin to cause him any harm, so his contingency is tailored to thwart those who can fight through the lich’s minions and actually get within range to attack.
Stating "loss of mental faculties" protects against a whole wealth of conditions, as you note (sleep, feeblemind, etc)…
No. Elminster’s Evasion does not protect Elminster from loss of mental faculties. It teleports him to his safehold after he’s lost them. It’s up to the DM what that means exactly (Int at 1? Unconscious? Dominated?), in the same way that it’s up to the DM to identify what “successful attack” means in Azalin's case.
…while stating "any time anyone casts feeblemind at me" only protects against that single spell, and not Touch of Idiocy, etc.
This is a good example of a clearly-stated trigger that is too complicated for contingency to handle.