Regarding the explanation for the micro coils' unusual properties: when you get a dry hit on a micro coil with cotton wicking, pay attention to the taste of said dry hit. You'll notice that there's no taste of partially-burnt glycerine, unlike on other coils: there's only the taste of cotton smoke.
This unusual phenomenon has led me to believe that the micro coils' secret is in the fact that they're heating the entirety of the wicking material within the coil rather than only the volume directly surrounding the wire.
That, in turn, would allow for two things: the high vaporization rate, because heat applied to all of the wicking material leads to all of the liquid there evaporating at the same time, and the lack of noticeable temperature gradient within the wicking material, because heat is mostly spent on evaporating the liquid, has no local peaks and thus spreads relatively uniformly. The uniform temperature gradient, in turn, means that the vapor doesn't have to go through overheated wicking material that may cause it to oxidize; in other words, it leads to higher taste quality.
*Note, however, that this is only a hypothesis and I don't have the means to validate it experimentally, so it may turn out to be wrong.
UPD: Oh, whoops, didn't notice that OP's question wasn't why micro coils work so well, but rather why we like micro coils. Here's the answer to that question:
1) These things vape like beasts. A single 2.7 ohm single micro coil I'm currently using puts out tastier, thicker, bigger clouds of vapor than a 1.3 ohm double coil does on the same RDA.
2) A good micro coil is easier to build than a good normal coil: you don't have to eliminate hot spots or worry about whether there is enough space between the wraps. Just wrap it as tight as you can, then press the wraps together and that's it: you've got yourself a good coil.
3) Micro coils work on lower wattages and (theoretically) have less heat dissipation; they don't heat the atomizers to scalding temperatures during heavy use. I like having my lips intact and my fingertips sensitive.
4) Many configurations with micro coils perform extremely well below the 2A current limit, unlike most other types of coils. I just like the idea that we can use eGo-type devices and even analog lookalikes to achieve the kind of performance that was, until recently, only reachable with the use of mechanical mods and IMR batteries.