There have been several discussions where shortening the line has come up, but nothing coherent. Those who want to keep the line seem to think that the often-heard proposal is to abandon it. Instead we should move towards shortening the line to use fewer units to accomplish the same purpose.
The line will not help us against a concerted attack by a determined foe. If someone wants to declare war, they can gang up on a weak point and break through, and with horse-based units could beat us in the race back to our own undefended cities. Even worse, many of our cities are undefended and an easy walk from a galley.
We need to quickly move our forces on the line to perform the same function (settler barrier) while using fewer units. As an example of carefully withdrawing the line, here is one turn of a movement plan.
By withdrawing sections of the line in synch, and leaving garrisons behind in cities which would end up outside the line, it is possible to achieve this configuration. As can be seen in the picture, the proposed new line can be held with 11 units, where the existing line has 23 units. This would allow us to use the remaining 12 units to garrison our undefended cities, and it can be done much faster than building new defenders from scratch, without breaking the budget or interrupting production of cultural and scientific improvements.
The line will not help us against a concerted attack by a determined foe. If someone wants to declare war, they can gang up on a weak point and break through, and with horse-based units could beat us in the race back to our own undefended cities. Even worse, many of our cities are undefended and an easy walk from a galley.
We need to quickly move our forces on the line to perform the same function (settler barrier) while using fewer units. As an example of carefully withdrawing the line, here is one turn of a movement plan.
By withdrawing sections of the line in synch, and leaving garrisons behind in cities which would end up outside the line, it is possible to achieve this configuration. As can be seen in the picture, the proposed new line can be held with 11 units, where the existing line has 23 units. This would allow us to use the remaining 12 units to garrison our undefended cities, and it can be done much faster than building new defenders from scratch, without breaking the budget or interrupting production of cultural and scientific improvements.
This half step of pulling the line back is just a way to light a fire under the military to make some changes. 
