Ugh, we're on some pretty philosophical things now, and technically the various cultures and beliefs of the Planes have different definitions of what is alive and what is not, and there are certain things that are frequently argued over by Reniam philosophers, like whether undead are alive, or whether dead spirits in the afterlives can still be considered as in possession of something that can qualify as "life", whether immortals are alive, whether plants are alive... heck, some of the most extreme views even questions whether animals and monsters are alive. Some might claim that the presence of magical energy is the trait that defines life, which creates doubt about the nature of such as Minions and reanimated corpses, others that it is the possession of a unique soul, which in many cases except plants (since these often share a soul with their surrounding plants) and would leave out things such as Harvesters, which have a different kind of lifeforce compared to most other beings.
If I, as the creator and demiurge of the universe, were to define what life in the Planes is... it would be that which is capable of affecting the course of fate. To someone who can see possible futures it will be evident that things that happen by chance are predetermined and will happen regardless of how many possible futures one takes into consideration, barring of course those that remove chance from the equation, whereas things that happen because someone decided something will be different every time. The web of fate is made up by a multitude of futures formed by countless decisions, and that is what life in the Planes is; the ability to make decisions.

What mages feel when they are subjected to magical exhaustion is rarely actually organ failure, though this is indeed one of the reasons that severe magical exhaustion can at times take a very long time to recover fully from; rather what one feels is the little things, things that are unlikely to be lethal but are immediately painful and/or crippling. Any experienced mages draining themselves a lot but not feeling a lot of the usual effects of exhaustion would actually be a lot more concerned than if they had been in searing pain, since the lack of pain meant that the damage inflicted by magical exhaustion was targeting something not immediately felt... which among other things could mean that they were suffering consequences that could kill them over time. What does kill them quickly is mainly when an organ responsible for short-term survival stops functioning altogether (the heart is the most common and quickest cause, although the lungs are also an ordinary cause, while somewhat slower), which the exhaustion can cause directly or indirectly (such as with a blood clot or internal bleeding). The brain is actually extremely rarely affected by magical exhaustion (directly, at least... indirectly still suffers frequently, which is another cause of immediate death) to a lethal degree, and even more rarely in a non-lethal manner. I could explain why, but then I'd start moving onto information that will actually play a major role in extremely late IC story, so I'll leave it at that.
I think I touched the subject of the relationship between soul and brain in Reniam once before... they cooperate, each storing information on its own in itself but mostly they will work in complete accordance with one another, although the most notable difference would be that the soul solely deals with thinking and feeling on both a conscious and subconscious level (which the brain also does), and whereas the brain is the only of the two responsible for "automatic" functions of the body. Memories are stored in both soul and brain, although the memory of a soul is more fickle than that of a brain, and tends to hinge even more on emotions. As for the mind existing separate from the body, what exactly do you mean by that?
The last bit, about why the body is altered to fit the soul, I will also have to abstain from explaining. There is a reason, but it is plot-relevant, so one day it will become evident. For now, though, let's just say that this is how it is, and leave it at that.

I do know about the technique of half-swording, yes (I was unfamiliar with the term itself, admittedly, although I did guess correctly as to what it referred to, as I confirmed by googling it), and I do have that up my sleeve to use when it seems appropriate, but somehow that hasn't seemed like it has been the case thus far... The people I have described fighting with swords have either been relatively inexperienced (various crusader grunts), had their blades wrapped in fire (rune mages and Goldheart Templars) or been Jaelnec, who uses Roct, which is perpetually significantly sharper than regular bladed weapons can reliably be due to its higher durability and thus not entirely safe to handle by holding the blade. The only sword-user I've written as for whom it would actually have been appropriate to half-sword was the vampire follower of Rilon at the Schaxathris church, and she was highly aggressive in her fighting and relied a lot on speed and reach. There may have been others, but frankly there just hasn't been a situation in which someone would actually have half-sworded yet.

EDIT: What do you guys think of the new Prophecy-banner?