Something so simple can be complicated if you're poor enough.  The camera pole developed a hair more friction.   Then it started jamming, revealing the servo didn't make any torque at its highest speed.  The trick with servos is they don't make any torque at their rated speed.  Their rated torque only happens at low speed.  They automatically slow down as the load increases.  A stepper just stalls.

Running it on 6V buys more torque, but the raspberry pi can't run on 6V & it's still not jam proof.  There's actually a sharp cutoff between high torque & low torque.  The cutoff rises with increasing voltage.

More importantly, the L6234 falls over below 6V.  The camera pole originally ran on 6V before the raspberry pi.  There would have to be a different regulator for the raspberry pi or a lower speed would have to be found for the camera pole.

There can be 5 more wires to the motor sensors.  It can go back to stock servo firmware, with PWM being used to control speed.  Its Silabs F330 microcontroller could be reprogrammed as a stepper driver to run on 5V.  Stock servo firmware with PWM is unlikely to be precise enough.  The rest are a lot of work with little payoff.  

No-one has ever hacked a servo's firmware.  Using the sensors would entail making a speed governor instead of stepping on a schedule.  The most effective solution is using the F330 as a lower voltage stepper motor driver.

The camera pole has always used a stepper motor out of a belief it offered the most speed control.  If speed governors are the future, it would be a lot easier & smaller to use an N-20 gearmotor with some encoder.  It could be a use case for back EMF but it would take some testing to see if the range of motion was enough for back EMF to be stable.  The easiest solution is just an open loop H bridge driving an N-20 gearmotor, but the N-20's in the apartment are too fast.  It would need some ramping for the PWM & it wouldn't be predictable enough to use machine vision.

There are other gearboxes in the apartment which could attach to stepper motors, but they're big.  Stepper motors are big because they need a big old motor driver with heat sink.

The original pancake motor with gearbox never failed.  It was just big.

https://hackaday.io/project/187734-convert-a-brushless-servo-into-a-stepper-motor

The decision was finally made to hack the servo to use its own 5V stepper motor driver.  That 7 day investment solved the torque problem, reduced the voltage to 5V, & freed up another L6234.

The camera pole came back with a vengeance.  The total power consumption with lion tracking was still 350mAh/mile.  All this stepper motor work is quite worthless compared to a 360 cam.  Maybe it's worth it if you have spare parts to make up for the $200 of mecha it would require from scratch.