I mean, it's pretty obvious. Even the most benevolent, utopian government will eventually become corrupt by necessity, because they will have to constantly defend their ability to continue to do good things, and the only way to do that is to increasingly expand their power to eliminate political opposition.
This is all pretty well covered by The Lord of the Rings... you don't give power to people who are good at wielding power, because while they might solve some immediate problem, they will concentrate that power and become corrupt very qickly, because they understand how to exploit power. You give power to well-meaning but naive idiots, hope they do a little good for a little while and then lose or disperse their power before they become corrupt. The point is that it's ultimately, it's better to give power to people who will squander it instead of people who will concentrate it, even though the instinct is to do the latter.
Leto II does what no one in history really has done, he concentrates literally all the power in the galaxy and then disperses it.
I think Tolkien and Hebert were exploring fairly similar themes, but Hebert was more focused on these bigger-picture, civilizational and intergenerational manifestations of power in the 2-4th books, while Tolkien was more interested in the specific arc of the individual's relationship to power.