I've read Treasure Island. I've also watched Treasure Planet, which has its charms, and definitely went to re-write Island on Disney's terms.
Not always perfectly. But it's odd to notice that they had to make the crew all pirates in the movie. You'd think that increasing the number of villains would make it worse, but this way they could finesse the problem of disposing of the honest hands, who could not be corrupted, In the book, of course, Jim gets to witness the treacherous murder of one -- triggered by hearing the death scream of another honest sailor.
Though the movie did have an alien captain, who might actually, unlike a human one, love gold for gold's sake.
When breaking a story loose from its frame to change something like that, it can be very hard to avoid being trapped by the old story