I would not be opposed to a fifth gate, but I do agree that it would be nice to spruce up the existing parks (not that I am complaining about their current state): The Magic Kingdom could use a new E-ride, a Fantasyland expansion and maybe even a new restaurant, Epcot also needs a new pavillion in Future World and World Showcase need to be fleshed out a little better or expanded, Disney's Hollywood Studios looks like it is gearing up for a new wave of attractions so no complaint there (except that an e-ride attraction would be ideal near the Lights, Motors, Action show), and Disney's Animal Kingdom just needs more stuff in general; a North American or Amazon Rainforest area would be truly inspired and the addition of Beastly Kingdom has great potential.
I do not have all my facts straight about Night Kingdom, but when compared with EPCOT, Disney's Hollywood Studios, and Disney's Animal Kingdom, it seems less inspired. If the Imagineers could come up with something as ideal as the aforementioned parks, I would be pumped for the addition. DisneySea wouldn't be a bad idea either. :king:
I look at the parks and I don't see major weaknesses in the Magic Kingdom. I think the addition of an E-Ticket (like Little Mermaid) would be gravy at this point, when the park is compared to the other 4. The refurbishment of Space Mountain will improve that park, but of the 4, it is last on the list for necessary improvements.
Epcot's Future World does have it's weak points when you look at Journey into Imagination and Universe of Energy, but those less intense attractions are necessary, and given the rumored upcoming refurbishment of Journey into Imagination, I'm not particular concerned with Future World either. I just wish they'd rename it Discovery World or some varient. World Showcase however is definitely in need of a blockbuster attraction. We've heard rumblings of Mt. Fuji making a return to the Japan pavillion, but my understanding is that Expedition Everest took some of the ideas for that, and the likelihood of that being created in it's original form are relatively slim.
Hollywood Studios seems to have a bright future, and it already has two high capacity thrill rides - the problem is they're right next to each other. I think the long rumored Pixar themed coaster is going to have similar capacity issues (See: Crush's Coaster) that Toy Story Mania has, and part of me is bothered by this trend of low capacity, high demand attractions (Soarin, Test Track, Toy Story Mania, and Nemo Subs at Disneyland). This can be diffused with another high capacity E-Ticket at another area of the park, presumably the backlot area.
I don't feel that the Animal Kingdom has glaring weaknesses other than DinoRama. However, I expect that to stay, as there are other locations for expansion that won't require the removal of attractions. Like many people on here, I would like to see Festival of the Lion King moved to Africa, and have Camp Minnie Mickey rethemed into something else, be it an Adirondack/North America area (where Pocahontas would fit in), or something completely different like the rumored Jules Verne area. It's well known that the original incarnation of Beastly Kingdomme won't be returning, but I have long been supporting the idea of a European section that would house many mythical animals. This could be placed in either the Camp Minnie Mickey section, or in the Flights of Wonder area.