Bear in mind that Illuminations takes place on the lagoon in Epcot, and can only be seen from inside the park. It's not like Wishes, which is a fireworks show and can be seen clearly outside MK. You may see some of the higher Illuminations fireworks from locations outside Epcot, but you'll miss the images projected on the globe, and the music, water, fire and lighting effects.
The only restaurants that provide a clear view of Illuminations are Rose & Crown in the UK, and the Cantina in Mexico.