If you're writing code and something keeps throwing nasty exceptions, you don't remove the exception handling - you fix the code.
Death penalty isn't the problem (leaving aside the traditional death penalty debate for a moment). Innocent people being found guilty, often by highly (and unnecessarily) faulty process, is the problem.
Cutting out the death penalty just hides the problem. I'm not saying that it's a bad idea to avoid putting these people to death, but the actual problem needs to be identified and dealt with.
Cases of such magnitude need rigorous scientific oversight, not just the say-so of whatever self-proclaimed "expert" was on hand to drag into court that day.