Radical? By no means ... But then again. Some people do call me radical at times ...

It's always just a matter of perspective. For example: You could create the false physical image of an elf (something like tridphantasm). This fake image would fulfill LOS and plane requirements. Yet you couldn't even start casting a slay(Elf) spell, since you do not have a valid target. But once you try casting a slaughter (Elves) spell, you can easily do so, suffering drain and still not affecting the illusion of said elf, since it's still an invalid target. Even an elf-poser could stand right in that area of effect without suffering any consequences. So from a certain POV the spells or better magic as such has to "know" what currently is a valid target and what not, especially when compared to the unlimited versions mana bolt and mana ball.

And this "conscious" target selection comes again into play when looking a sustained spells with an area effect (with a hard range limit in direct versions *spell radius* and a soft range limit in indirect versions *any observer no matter how far away*), where potential targets can walk in and out ...

So under your theory when you fail to get enough successes to say fool a high tech visual scanner ( 4 threshold ) then your spell just wasn't strong enough to affect a technological device with such a complex pattern and as such those high-tech devices can see through the physical invisibility as if it wasn't there. As for living creatures your version of the spell operates on them almost identically as the mana version. But here is where I think it starts to fall apart. Because the mana invisibility spell and the improved invisibility spells affect living viewers differently. One is resisted by willpower and the other by intuition. The other major difference is that when you resist a mana illusion then you're able to see through it but resisting a physical illusion merely allows you to determine that it is fake. If the improved invisibility spell still works by affecting the "form" of a living object then shouldn't resisting it also be a matter of Willpower?

You have to decide whether the image the viewer sees is from detecting the photons ( or rays of light ) hitting the other side of the invisible object or person. Or if the image is formed by manipulating the mind or eye ( or technological equivelent ) of the viewer so he doesn't see the invisible object. In one case the image the viewer sees is correct in the other case the image is what the user expects to see.

Basically, you have the flashlight working the same as it would with the mana version. But I'm not even sure a viewer could see the flashlight even with mana version. The invisible subject, anyone he chooses to let see through the invisibility spell, and those who make their resistance check can see the light from the flashlight. But can a guard who failed his resistance check see it? I doubt it. The mana version edits the visual image from the guard's mind and all visual clues that the invisible subject is there. CLues which include the flashlight and the light it is generating.

Not at all. Except for Decrease Willpower no physical spell is resisted with Willpower. This may simply be the nature of physical spells. Consider for a moment mind altering drugs. Certain drugs attach themselves to certain chemical receptors on the brain. This produces certain effects. The effects differ depending on the receptor that the drug attaches to and this depends on the shape of both the chemical and the receptor. Perhaps mana invisibility is shaped so that it can attach to a receptor that is tied to willpower while inanimate objects do not possess this receptor. On the other hand, physical invisibility is shaped so that it can attach to a receptor that is tied to intuition.

Also, the text does not say that resting a mana illusion completely removes the illusion nor does it specifically say that resisting a physical illusion does not remove the illusion.

Resisting a gunshot, for example, does not mean that you were not shot. It simply means that the gunshot does not cause enough damage to be considered a wound under Shadowrun's abstract system. It is quite possible that a resisted mana illusion leaves some traces of the illusion and it is just as possible that a resisted physical illusion does not leave any more traces than the mana version does.

Again, this is not so. It is possible that the viewer sees the correct image in both cases. Metaphysics requires internally consistent logic but it does not have to be consistent with physical reality. By influencing sight as an abstract concept instead of altering photons this system actually avoids a great deal of mess. It is little different from a limited version of clairvoyance (which is a mana spell and thus cannot intercept photons).

In such a case the individual cannot see the flashlight or the light it is generating. The individual can see things that are illuminated by the flashlight but has no clue that the object is illuminated without resisting the spell.