Does anyone know if you can exchange the knobs?
What knobs do you recommend if you could?
I‘m asking for a friend of a friend. 
If we’d know what the problem is, we - maybe - could give some advice.
For me, I like the little encoder knobs of the m:c very much, much better, that the longer plastic ones on my craft synth 2.0. They have a good grip and seem to be made of gumlike plastic. Ideal for myself.
The only thing I could think about would be to have them in different distinct colors.