Re "smoother shifting" or "under load", I've often wondered how shifting is in regular riding with proper letting up of pressure when shifting. For touring I've often thought of ideal cassettes that start at 13 let's say but give a more useful couple of closer matched cogs in the range of speeds we often are in touring. The 9 speed 11-32 is a good example where I'd be very happy to drop the 11 and maybe even the 12 to get a couple of often used cogs in the middle ish but still having the 32.
Guess the only way to really know would be to try it, as one persons rough shifting might be fine for someone else.
One could carefully grind off the short notch off of the cassette... and then turn each sprocket any which way.
Most of my bikes still use friction shifters... I've gotten up to 9 spd, which seems to shift smoother than the old 5 speed clusters. I've ridden a couple of 5x2 bikes lately, and they just seem a bit crunchy with the shifting.
My one indexed brifter system (also 9 spd) just seems pretty touchy. I do think it would do a lot better with a very tight B-Screw adjustment, which all depends on the cassette/derailleur match.
When everything is working right, one can smoothly shift without any slippage.