Hi Mr Probert.
I don't comment often. but on this subject I will.
The earliest rendition or inclusion (on screen) of discernible 'Escape Hatches' were on the Ambassador Class Enterprise captained by Rachael Garret in 'Yesterday's Enterprise'.
Given that that ship existed in the historical period of Khitomer 2293
, the war with the Klingons, then it seems likely that the hatches on the saucer were not for escape, but deployment of ground forces. There are onscreen references and inferences that I think support that contention.
After the Khitomer Accord, tensions relaxed and the need for troop ships was no longer required.
Long story short:
Federation and StarFleet used the bigger troopships (E-C) to utilise the combat experience of the E-C to man-manage increased personnel of the 'Town-Ship' that is the E-D
My point is, no specific escape or deployment systems were onboard a starship prior to the Ambassador Class
Tha Saratoga and other Miranda Class ships used 'Lifeboats'. Individual vessels capable of direction independent flight and planetary touchdown. Life/escape pods are not.