I think even that is too long. Think about when that one second would occur: when the app you are using needs more memory, you are running low, and the system i

I think even that is too long. Think about when that one second would occur: when the app you are using needs more memory, you are running low, and the system is closing the least recently used app. Right at that moment is the worst time, user experience wise, to have a delay, especially a delay on the order of half to one second.