"Is it feasible to plan meals based on items that don't have to be cooked"
I do it about half the time on trips up to 10-11 days. Lots of nuts, chocolate, crackers, chips, olive oil, Nido powdered milk, Hammer Perpetuem and First Endurance Ultragen.
"can you get a nutritionally balanced diet while on the trail doing so?"
I find it harder to eat my normal, healthy diet going cold food because I don't like to fool around with mixing up hummus, cous cous, cracked wheat, etc. It takes time and a container, and cleanup. Other posters have lots of ideas for these more elaborate, and healthy, foods. My premise is that 9-10 days of a less than optimally healthy diet isn't going to shorten my life appreciably. My main goal is to provide adequate calories, properly balanced between fat(dietary and stored body fat) and carbohydrate, plus protein for tissue maintenance.