No big secret here....California Grill has one of the best views IF you can put up with the crowds and noise.
We like the view from the 'deck' at Narcoosees. Love to watch the electric water pageant and fireworks from there.
Love the Epcot view from the lounge in Japan (the name escapes me) and an outdoor table at Alfredo's to people watch. Also like to watch Illuminations from the Cantina in Mexico.
One of the most beautiful views for sunset is at Arthurs 27 in the Wyndham near Downtown Disney. This is an adult only venue...quiet, relaxed, upscale adult venue. Sometimes they give you a glass of champagne at sunset....FREE! Time it right and you can see the fireworks from MK and Epcot!!