The added footage is not necessarily going to make the movie any better. Good editing is every bit as important as good directing, a good script, and good acting in producing a final product that is worth watching. Most of what ends on the cutting room floor belongs there. There are a few exceptions (the original theatrical cut of "Once Upon a Time in America", for example), but from what I've seen of the restored footage "Apocalypse" isn't one of them.
The movie is an adaptation of "Heart of Darkness" by Joseph Conrad, a story originally set in Africa and that was a commentary on European colonialism. Brando's performance was quirky, but remember that his character was supposed to be "mad." Would it have been an improvement if he had played the role more as John Wayne might have?
In any case, I've found that those who don't appreciate his performance, but do get an erection over the Col. Kilgore character, are better served by watching the "Missing in Action" series with Chuck Norris or Stallone's "Rambo" movies. Those movies aren't any more realistic, but then the Kilgore-loving viewer is at least admiring a character who is MEANT to be admired. If you actually pay attention to the sequence concerning Kilgore, including Sheen's voice over, the message is that Kilgore is a swaggering fool who will get lots of people killed, although he has "that glow around him" and will probably never be injured himself. That image is further reinforced during the "Charlie don't surf" sequence. Remember, "Apocalypse" isn't an action/combat movie, even though there are scenes of spectacular violence.
"Apocalypse Now" was a brilliant, but flawed, movie. IMO, the added footage will magnify the flaws more than the brilliance.