Would it be fair to say that a catastrophic MD-80 crash might be less survivable than a more modern aircraft? Specifically, I'm referring to the accessibility of exit doors and the lack of fire suppression systems.
You term it a 'catastrophic' crash and in that case, all bets are off. And if there is enough force to break the fuselage, there is also probably enough force to rupture the fuel tanks. And with 30-40,000lbs of fuel, the fire as well as smoke and fumes diminishes any chance for survival. Also with enough force to break up the fuselage, there is the possibility of blunt force injuries.
Remember that accidents are the exception and each one has a high number of unique factors. So, is the -80 less survivable? I don't think anyone can make the argument.