Yeah I don't buy the baseline comparison of the "expert designed controller" that cannot stay within bounds. We can control systems that have not only fluid-mechanical, but also heat transfer and chemical reactions, all happening at the same time with huge bars of uncertainty. Next.
Between prevailing winds, power and superpressure limitations, etc., it is often the case that a balloon cannot be regulated within bounds regardless of the quality of controller. Nonetheless I’m certain there are better control laws than this solution.