I see people ranting about the castings of the lotf show so I wanna put in my own two cents
I don't mind any of the castings truly, but I feel like the original appearances adds a lot to the characters. (Symbolism)
Ralph being blonde+white can be compared to him being the "golden boy". As he gets dirtier from staying on the island, he is no longer golden, and falls from grace.
Jack being a ginger also adds some. Gingers tend to be slightly ostracized, or made fun of. Being ostracized or made to feel lesser can make the person have a desperation for power, like Jack did.
Simon being poc can very much be compared to Jesus. In fact, his whole character can be. Simon was the only one that saw The Lord, and then when he died, he was filled with holes, much like Jesus was. Jesus was not hailed as a hero by many, instead found weird and not worthy of trust. Sounds familiar.
I'm not sure about the symbolism with Roger, but being poc can likely coincide with the timing the book was made. In my personal experience, being bullied over the years has led me to also be brooding and have violent tendencies/thoughts. Because Roger is poc in 1940s to 1950s England, he's guaranteed to be bullied, and almost certainly worse than I have been.
Idk what I'm talking about tho don't trust me