Well, I have just been mulling this around for a while. But here it goes.
The product that we call "smoke" is a mixture of Glycerin (or glycerol), burning sugar (from the honey), and some tobacco. Not enough tobacco is actually cooked (or burned) to produce visible tar (as we know it), so in that regard, hookah smoking is much safer, can can be compared with Electronic Cigarette.
In the E-Cig, the product used to create "vapor" is propylene glycol. PG is a converted form of Glycol (a process that uses a catalyst). Glycol is absorbs water from the air, and when it is super-heated, I would suppose that it's vapor would very easily absorb water (from a container of water). When we pull through the hose, we pull down the vapor form of glycerol, mixed with a flavoring, binded with lipids from the honey (if there is honey), mixed with a mellow form of burning tobacco product (which is very saturated). The glycerol absorbs water as it is broken apart from the surface of the water into bubbles. This is what gives us the very thick vaporous clouds, that don't sting our throat. This humidified glycerol also sticks to the inside of our hoses, stems, vases, bowls, and especially our grommets (which causes silicone Mya grommets to feel greasy after a session). This filmy stuff is actually a lubricant, and washes off easily with water. Glycerine by itself would cause bistering on any membrane of the human body that contains water becasue of it's absorbtion properties.
When we add more heat, the tobacco itself starts to actually burn, causing the vapor we inhale to actually become a higher percentage of hot tobacco particulate smoke, which in turn burns our throats. The feeling of Nicotine on the throat is different, it is also a "burning", but more tingly than hot. This is what one experiences with Tangiers tobacco.
Tangiers tobacco is unwashed and contains mostly black tobacco product (which has a very robust flavor by itself). Tangiers contains Glycerin (plant-derived) and molasses (black), and also a high amount of nicotine. The nicotine causes the throat tingle, but so does the burning tobacco (which is easily burned because of how much there is), and also the bunring sugar in the molasses. This is why one must be very careful with Tangiers, and if there was no flavor one would be able to simply taste the tobacco flavor mixed with the sweet molasses (which would be fantastic).
Nakhla is just a very light flavored golden tobacco that has a very mellow flavor, but it is slightly washed, other wise it would be as hard to manage as Tangiers and you would in fact taste the tobacco slightly. However, Nakhla uses Honey and lighter, mroe natural flavors to create their finished product, which is why it is so popular.
Other tobacco products, Starbuzz/Fantasia/Al Fakher/etc. wash their tobacco of all nicotine. This makes the leaves themselves very flimsy and crumpled (they are basically destoyed) and utterly flavorless. All this is done in a factory, leaning towards mass production over quality. These leaves have absolutely no value in the over-all product.
All they can do is burn, and casue a burning flavor to appear. They add no flavor to the shisha, and even though the glycerin isn't burning, the tobacco is, so it has no point.
What I was thinking, as well, is that just a mixture of Glycerine or Propylene Glycol (I would go with the latter) and flavor could be used in a hookah. It would be much easier to deal with heat management, you would get even bigger "clouds" if that is your thing, and the flavor would be great as well. I would say PG would be safer because it is non-irritating. The over-all cost of shisha would go down because companies would no longer need to waste money on tobacco. This does not relate to HookahHookah, Nakhla, or Tangiers.
These are some things I was thinking about.
. I am going to try this glycerin thing out I think. I'm gonna try to find Prop Glycol first though.