Basically having a Sine Sub-OSC isn't especially useful because it's purely a fequency boost at the root note an octave below. Because there are no harmonics, it doesn't boost the low end of the existing wave or mesh that well with it. A Triangle wave would have been a better choice as it would have offered a similar effect to the sound wave while having some harmonics.
An even better solution would to have a selection between Sine (1-33 levels), Tri (34-67 levels), Square (68-100).
I know the Microbrute a sine wave one but generally they're not used as often for a reason.
