I'm considering removing the driver motor from the extruder assembly, and placing it on a stationary mount point instead, and then using a flex-shaft type connector from the motor to the extruder assembly to actually drive the extruder. The motivation for this change is to reduce the overall weight of the extruder driver and hot end assembly, allowing for quicker movement of the carriage on it's associated axis(one of X,Y).
Would it be better to run a pair of drivers (one for each direction) to manage reversing the filament pressure or would it be better to use just one driver and reverse the motor as usual?
If you're talking about a common 3D printer stepper motor and driver, then one driver is perfectly capable of driving the motor both forward and backward.
The flex tube setup you describe sounds like a Bowden extruder.