AC is much easier on switches (the arc which occurs when opening the switch is extinguished at the next cycle, instead of the more sustained arc which occurs with DC).
AC is safer for humans, especially at high voltages. DC causes muscles to clench onto whatever the person touched, while AC makes you kind of jump away a bit more.
AC works with the rest of the power grid: synchronous generators, transformers and other heavy-duty equipment all rely on AC. DC alternatives are much more complex.
Edit: ah, I see you're not necessarily proposing we get rid of AC. In that case, having two systems would be complicated.
AC is safer for humans, especially at high voltages. DC causes muscles to clench onto whatever the person touched, while AC makes you kind of jump away a bit more.
AC works with the rest of the power grid: synchronous generators, transformers and other heavy-duty equipment all rely on AC. DC alternatives are much more complex.
Edit: ah, I see you're not necessarily proposing we get rid of AC. In that case, having two systems would be complicated.