Yes, that is a way to minimise damage, but with the wavespin you don't lose any speed at all.
Karts are still vulnerable to POW Blocks.
Sorry for firing all those terms at you, I thought I might start name the technique other then:"fling-at-the-right-time-upwards-when-a-pow-hits-you" technique.
I see, then I'll have to wait and see for myself when Brawl comes out in the Pal Regions.