Blockchain networks have enjoyed remarkable attention the past period in both the research community and the society at large. Such networks carry the promise of highly decentralized validation and witnessing of important social and economic events, reducing the need to rely on centralized authorities. Public proof-of-work based networks specifically, despite their limitations and challenges, continue to be popular today due to their simplicity and intuitiveness. However, for such networks to perpetually meet viability, efficiency, security and environmental sustainability objectives, they need to continuously adapt to environmental changes via self-reconfiguration of their basic governance parameters. In this paper, we attempt to formulate this blockhain network adaptability problem as one of control engineering. We identify the basic characteristics of the blockchain networks as systems to be controlled and sketch what variables are available for designing a controller that allows such networks to attain macroscopic objectives. By means of describing and simulating a simple idealized proportional controller, we demonstrate the benefits and some of the challenges in designing such controllers.