The trouble with SpaghettiOs is that they don't retain heat long enough - at least when microwaved according to the directions on the can. They get cold very quickly.
Giving SpaghettiOs a thicker sauce may increase the heat capacitance.
Change in Recipe
Changing the recipe in some other way for better heat retaining could make SpaghettiOs more popular. A thicker sauce may help with the overall temperature of the pasta.
Hallowed out Shells
Perhaps a hollowed out shell with a little moisture inside will help the SpaghettiO's keep their heat when microwaved.
The sauce stored with the noodles in the can may have something to do with the heat storage of SpaghettiO's. By having the noodles separated from the sauce may help the noodles from not becoming more saturated.