Hugelkultur definitely lends itself to good drainage and fertile soil. I have found very few plants that don't do well in a hugelkultur system. But just like any raised bed, you have to include other good soil along with the wood.
I think you're on the right track here. All of our beds are never tilled and each year they get better and better. I think the beneficial soil microbes continue to increase the longer the bed is left undisturbed.
