I've never heard anyone talk enthusiastically about a diesel cooktop, but it is certainly a logical choice for international travel for the reasons mentioned. A diesel cooktop is pretty much like a crappy electric stove - perfectly usable but no one who cooks with it loves it. Cooking with diesel smells of diesel outside the the camper. Not strong, but ode de bus station is not exactly gourmet.
I like having propane, but not for heat or refrigeration. If the critical systems don't run on propane much less is used. Plus there isn't the pressure of finding it in wild or unfamiliar areas.
The disadvantage I see with a "single fuel diesel approach" is not only the cooktop but the diesel generator. I would rather have solar panels and a little tri-fuel generator. Not arguing that an all diesel design is a mistake, just that it may seem a clearer choice in theory than in practice.