What are considered to be the disadvantages to having a single executive?

According to Benjamin Franklin, having a single executive is a disadvantage because he becomes overambitious or gets sick, leaving the country without someone in charge. There is also the concern that a single executive comes from only one state, and is not able to adequately understand or govern different parts of the country. A single executive is also reminiscent of the British monarchy, a model that many delegates want to avoid replicating.