From another thread (but the answer would be somewhat off topic there):
Kirby's intention (= what he said in interviews or to his friends and colleagues) isn't more important than his direction (what can be constructed and understood from the narrative itself). In any case, the satirical mode never overpowered the romantic one in his Fourth World work. So, Darkseid was never, ever, a pure satirical character (the exception maybe being The Hunger Dogs, but it was done by a later, more tired Kirby). He was never a representation of pure evil like many 'modern' comics would want us to believe. It's too easy a solution, too childish, too banal, but DC so desperately needed its own Sauron, and that's what we got. But original Darkseid had many admirable qualities - and that's where the fascination lies. And with it, the danger.
Complexity and ability to change are not necessarily connected, let alone being the same thing. So, I don't view Darkseid's inability to grow (as a character) as a handicap per se. He is what he is, and what he is can still be the greatest danger of our time, even nowadays - as any serious survey of the political situation worldwide will show us. And similarly to Aaron's take on the origin of Thanos, Darkseid had John Byrne, who thought he had the smartest idea EVER when he told us how Uxas had become Darkseid. Which is not only unnecessary but even harmful to the perception of the character-as-a-metaphor. Unfortunately, and sadly, Byrne's take on the New Gods was among the better uses of the characters...
Anyway, Darkseid and Thanos are different enough and complex enough that any opinion that favors either of them can be valid. (But I'll remind you that we don't have to choose one )