OK, I'll bite. I do support the death penalty as a default for murder and arson, but judges should have the power to overrule the default and opt for life imprisonment, or even life of exile beyond the limits of the city where the crime was committed, with a clear explanation of why he's chosen to overrule the default, where certain special factors need to be taken into account. I also think there should be a minimum age below which we shoud re-educate instead of giving the death sentence or imprisonment, let's say anyone under the age of 15.
I am aware that one of the main arguments against capital punishment is that no legal system could ever be perfect, and as such, innocents will always slip through the cracks. A flaw I see with such an argument, though, is that in that case, we could put no one in prison unless we were 100% sure they were guilty, which is rarely the case. By such a standard, few criminals would ever be prosecuted, so for public safety, we do need a middle ground, and that's what we refer to as 'reasonable doubt'. By that standard, we can be sure that few crimnals will go free and few innocents will be prosecuted.
So yes, there is always a risk of innocents receiving a death sentence, but that risk can be minimized considerably by having to prove the person guilty beyond reasonable doubt. And I do believe that the death sentence will deter at least some people from committing a crime.