Bob,
I've read enough posts detailing similar "miraculous transformations" to believe such reports without skepticism or doubt. Typically, they're about juice Delivery Systems---detailing a dramatic change in the vaping experience between standard atties/cartos/clearos and rebuildable atomizers, usually outfitted with micro-coils and cotton wicks. This one's a little different, in that the "Before" version is a Kayfun using a 1.6 ohm coil, with the "After" transformation occurring because the coil resistance was lowered and the wattage presumably increased.
I've not personally experienced anything similar. Juices taste pretty much the same to me whether atty-dripped, clearo-loaded, or bottom-fed into an RBA with a low-ohm coil (1.0 ohms is about as low as I go, but many of my bottom-feeder are run at that resistance). I've certainly experienced the somewhat muted flavor produced by early-generation top-coil clearos, but I find little difference in flavor between atty-dripping, quality clearos such as a bottom-coil Kanger T3 or dual-top-coil iClear16, and a low-ohm micro-coiled/cotton wicked small-chamber RBA/RDA. The difference for me between those three classes of JDS is in the essence of the vaping experience itself, with the rebuildables providing what I might describe as a more "expanded" vape than the other two types.
Bottom line is my frank amazement that any hardware upgrade could salvage those NicVape liquids and transmute them from dreadful to delicious. I regard your experience as nearly magical and truly miraculous.
If you are game we can swap a couple mls, see if you can replicate the results of this Double RY4 @ 18watts vs 10, also since I haven't tried any other RY4 before you can throw me a 'real' one to try.