Well if nothing else it's nice to finally get an answer on just what exactly the Whills are supposed to be.
And for those choosing to wilfully misunderstand the concept: he's not saying microbes control the force, he's saying that what is referred to as "the will of the force" originates from the Whills, which are omnipresent symbiotic creatures that exist at the micro, possibly quantum level of reality and use the midichlorians as symbiotic go-betweens to communicate.
The force itself is still a mystical energy field created by all living things, it's just the Whills seem to occupy the field itself at the quantum level. Just as you can stand in a still pool of water and make waves and ripples with your hands, so do the Whills manipulate the force and yet they are no more "the force" than your hands are the water. There's a direct relationship, but it's just that; a relationship. A symbiosis of sympathetic systems.
Which honestly would account for a lot of what we've seen the force do; Space, time and the laws of physics get very screwy at that level and any life-form able to straddle that gap would have a much different, higher dimensional view of the universe than we do.
ETA: It kind of brings to mind
this well know lecture by Carl Sagan.
It also seems to jibe well with the concept of the light and dark side being an expression of balance and disharmony, respectively. The light moves in sympathy with the greater whole, while the dark seeks to dominate and control the greater whole in an unsustainable parasitic relationship.