It IS a good film for the most part, but it really did need to be trimmed back in places, unlike Lord of the Rings which deserves the long running time due to how much is going on. In Kong there are too MANY moments where Peter thinks he's building tension by having pauses and slow motion that go on forever, but in order to do that successfully you need to make good characters and character scenes, but the ONLY character that's any good is Jack Black as Denham. So the viewers just want things to move on faster.
The effects are, of course, AMAZING, particularly the digital and physical recreation of 1933 New York, and Kong himself, but here we have the case of the effects being much better than the story and performances themselves (the Star Wars prequels were like this. I would definitely say that Kong is Peter Jackson's Star Wars prequel nightmare).
Adrian Brody and Naomi Watts aren't a good pairing in Kong. In fact, Brody is just miscast and shouldn't have been in this at all. Naomi does a good job but she's wasted because all she gets to do is stare in silence up at a giant ape for most of the movie. In Peter's 1996 Kong script Ann had an actual story where she was the daughter of an archeologist, and Jack was a WWI fighter pilot (IMO those characters and many of Peter's ideas at that time were just STOLEN by Universal for The Mummy which came out a year or so later!!)