( Though a pull request  for implementing this feature has been sent, this post is being made as 'CONTRIBUTING' document mentions discussing changes in the forum )
Current pedal assist provides cadence control. With such a control scheme, riding uphill on a gearless e-bicycle requires rider to put lot of effort during uphill (changing to low gear on geared bicycle with cadence type control makes uphill ride easier). Having Constant Torque whenever rider pedals would make riding easier uphill (as well as start) on gearless bicycle. Some of the popular (not high end) e-bicycles available locally seems to have this kind of control based on the riding experience. This corresponds to 'Basic PAS, constant throttle' of 'PAS Control Schemes' , with the difference that throttle setting in that article corresponds to speed, while here torque. The implementation is simple as well.
See pull request  for more details