That last point is interesting PB, the DC9/MD80 series were not very high off the ground especially at the front the tail area was a bit higher up as Irecall but may be wrong . So there was never going to be much of an angle on the escape slides anyway . . If the gear was up I would think most people would get out unaided . What did occur to me at various times (although I have to say I was lucky enough hat almost all my many SAS MD 80 trips were up front ,) was going out the back way meant having to go yintot he darkest part of the cabin and then into an even darker space and pass between the engines which of course are likely to be the things actually on fire if that's the cause of the emergency.. You wouldn't have easily be able to see where you were going compared to a conventional door or over wing.