Torque is related to the power output (power = torque x rpm), so obviously a higher torque motor is larger and requires more powerful electronics to drive it. Thus you don't want to over-specify the motor size for the load you are trying to drive, as with any electric motor. But, of course, you want a reasonable design margin (perhaps 50% over the anticipated load).
you are getting the right answer but to the wrong question. at any GIVEN speed and current, a high torque motor will have a higher torque.
conversely, at any GIVEN speed and torque, a high torque motor will take less current.
up to a point a stepper ALWAYS draws the same amount of current regardless of load or speed. beyond that point the current and torque start to decline.
At low speed a stepper coil is a RESISTOR. at high speeds you start to see the coil inductance reducing the current.