Instead of a Martial riffing on the fall of Rome how about a bloody minded Seneca coolly observing a dodgy patrician at the rise of the Cold War empire? All the makings are there and Aaron Eckhart makes a great greedy lizard-of-influence. Play it well and there's plenty of room for Thompson's daggers and foolery. Terry Gilliam has already shown how even as evenhanded a depiction as Fear and Loathing (seriously, look again if you don't believe me) can allow Thompson's anger through and still serve cinema. Plus, he still has to struggle to make his movies, and can still make great ones. I'd see it.
Remake as magical realist as you want but do it with an eye to the narrative timeline that will allow your audiences to care about the crises when they happen. Let the newly conventional Sion Sonno make this in Japan. He will find things in the treacley warmth that will rightly chill your central nervous system ... and turn this bowl of porridge into an adventurous eel miso.
Also, recalling this movie brought to mind other Depp vehicles from the time: Don Juan de Marco, Arizona Dream, Benny and Joon (which almost made it into this list and might well into the next), Sleepy Hollow ..... And that's not counting all the suspected horrors I avoided at the time like Chocolat or The Man Who Cried. He's an impressive screen presence, Johnny Depp but god he's made some rubbish.
But since it does have some good points and is only ruined by the execution it might be yet another candidate for a found footage/faux docco style that can actually justify itself. Get Michael Winterbottom on the phone. He'd work it.