Realistically it does have to have a computer, but not necessarily a visible one. Power motor control is tricky - it requires monitoring the phase angle between the drive currents and the motor position, as well as things like overcurrent protection and the ability to switch to regenerative braking. Oh and you'll want traction control in there because the torque is highest at zero RPM, unlike petrol motors.

Even electric scooter size motors will have smart controllers. They're a big market for microcontrollers, e.g. TI: http://www.ti.com/solution/dc-input-bldc-motor-drive