I don't understand why you think decentralization is a balancing act. What do you mean by "impossible to control", and why would that be bad? What would "full" decentralization even entail? A network of sentient computers doing whatever they want, except using supernodes "too much"?
(My definition of supernodes: nodes that transfer significantly more traffic than others structurally, in practice nodes that accept incoming connections, like servers or BitTorrent supernodes, but also AS's.)