We're also taking our first kidless trip in October for F&W (much to the disappointment of said kids!). We got tickets to the Party for the Senses on one night and are going to California Grill and Citricos the other two nights. We debated whether to just spend our dinner times getting more things at F&W but didn't want to lose the opportunity to eat at nice places without the kids....you know, like on a real date! I suspect we'll be order a bit lighter at the restaurants that we might have without having grazed around Epcot throughout the afternoon, but if it turns out to be just an appetizer and a beverage, then that's great, too.
As for other places that might be low on kids, you might consider Jiko or Sanaa over at AKL, as they have menus that while not crazy might also be less appealing to young kids on the average day. I have also become partial to the Epcot resorts area, which has great restaurant choices like Il Mulino (an absolute favorite of mine), Yachtsman, Bluezoo, Shula's or Kimonos (sushi). Haven't hit them all quite yet, but that whole Boardwalk area can make for a fun night and is obviously just right out the back door of Epcot if you're already spending a lot of time there for F&W.