sub-ohm RBAs usually have a lower gauge resistance wire than other normal atomizers. These wires tend to produce better flavor, vapor and throat hit than higher gauge res wires. This is what I believe, but I could be wrong. I happily vape at 25 watts with a 0.7 ohm AGA-T2 and a freshly charged battery on a mechanical.
My setup is almost exactly the same! 28g kanthal at 0.8ohm on the T2. Love it!