One of the biggest weaknesses in highly centralized authoritarian regimes is that it creates enormous incentives for the largest assholes to lie, cheat, steal, and kill to get into power, because one they're in power they will be free of any consequences. This also means they have to be exceptionally regressive towards the population because they know the next huge asshole will be itching to do the same to them. With decentralized power you can have checks and balances to punish people like that.