The California Grill lets you go out on the observation deck. You need reservations to get up there, though.
The Polynesian is said to have a nice view from the beach. The Wishes music is played, at both places.
Was at CG once, with window seats and stayed right there. It was very nice.
Another time, seated on the far side of the restaurant, so we went to the obersevation deck.
Your best bet for a window seat is to have a party of two and ask for MK window view seating, when you make the reservation. They won't promise it, but it doesn't hurt to have that information, on file.
Other than that, you can eat at the Roaring Fork at WL and take the 9:30 boat to MK. The boat will stop and dim its lights on the water, while the Wishes program goes on. Then go for a cruise back to WL, or get off and take a monorail ride to the parking lot.
This might work from GF, but I don't know the boat timing.