I guess that makes sense, especially considering it is your projectAs a designer I have to remind myself quite often that not everyone does or see's things the same way I do. I dry camp a lot and as such place a premium on water storage, but not everyone else does--most don't in fact. Most don't do 14 day trips, etc. You would put a refrigerator in--I think that is a terrible use because I prefer a dedicated cooler with actual capacity--not a tiny little unit shoehorned into the slide out where it is hard to use. The point is, your suggestion is not wrong--it is just the way you like to camp. Saying the many people that prefer baskets should want less practical drawers is another example.
I think putting an actual faucet in the sink and 5 gallon water tank in the slide out is impractical when I can have a 14 gallon frunk tank with a pump and sprayer 4 feet away, but MOST people prefer a faucet. They are not "wrong" they just prefer to do things a different way.
My approach has been to make the slide out strong, light weight, and weather proof. The individual compartments are fairly versatile and there is room for people to configure things the way they want them to a fairly large extent. There are drop in propane cook tops that fit the available opening for the one guy who wants propane in his EV. If you don't want a little 5 gallon tank and faucet and would prefer to use that space for storage, (like me) than you can easily do that. If you only want a single burner--again like me--than that can be done too.
With good solid "bones" to work with--in this case a high quality carcass--there are lots of options.
My thought has always been the entire camp kitchen concept is completely impractical for overland/backcountry/camping. It will mostly be utilized as a tailgating accessory, which it will work well for, both yours and the original Rivian concept.
should have called it the tailgater package.