Illuminations is so huge, you can see it without being right at the edge of the lake. You can get lakeside viewing from the Rose & Crown in England and the new Mexican cantina La Hacienda de San Angel. Tokyo Dining in Japan has a view from their front windows on the second floor. Chefs de France has limited viewing. They are on street level so there will be standing people blocking your view. Bistro de Paris is upstairs and only has a few tiny windows. I was eating there once (don't recommend it) when Illuminations was happening and the view was very poor. Nine Dragons has some viewing but it's not optimal.
My advice is to eat around 6:30 or 7pm, so you are done before Illuminations and just watch from the many areas around the lake. Like I said, the show is so massive, you don't have to be at the rail to see it. If you don't have to leave right after the show, a nice place to watch is from the courtyard of the Japanese pavillion but there are other paths towards to mouth of World Showcase if you want to head back to the buses ahead of the swell of humanity after the show.
