Very good points.
To be honest I don't think food will be a complete feature unless we add more "complex" elements to it. It doesn't need to be ressource consuming at all, but several mechanics must be compounded together so that the whole food/hunger gameplay becomes engaging and thoughtful. Food spoilage, as it has been discussed previously isn't in my opinion a solution that will enhance gameplay on it's own (if at all).
What makes 7DTD unique is the fact that a lot of different, seemingly independant mechanisms and "mini-games" are actually tied up together, thus making the whole a rich experience. The aspect that is truly making food management feel lackluster is that it is focused solely around quantity management. There's no need for diversity, there's no real gain from any food; the game theory behind all of it relies on two equations, ressource cost/hunger regen ratio, and hunger regen/health regen ratio - and you choose your recipes depending on if you want to maximize either food cost or healing efficiency. Then you figure out which is the easiest food income for you and you repeat the process just like a daily chore.
Things would be much more interesting with another layer of thinking. It could be as easy as granting temporary "special bonuses" depending on your food intake (bacon & eggs make you hit harder but move slower, vegetable stew would increase your stamina, etc). Or you could think about a whole system, something like having to fill 3 bars instead of one (don't use carbs/protein/fat though

), and getting bonuses or debuffs based on the diversity of your diet.
It doesn't need to become YourFitnessPal simulator, but if I can fill myself with the same food over and over again, it's always gonna feel too one-dimensional to be interesting.