Full on randomization of shapers on a scale from for instance smooth to spiky character for the randomization, degree of randomization of the shaper curve (should be possible to make the shaper look kind of like the noise and mess waveforms with spiky character and 100 % randomization).
If you can do this I'd also find it very helpful with an option to randomize several shapers within one a modulator at once and set the degree of difference between them in %, with the chosen shapers completely identical at the lowest setting up to as different as possible. That would probably require one of the chosen shapers to be the starting point for all of them to make most sense, perhaps always the one highest up on the list so there won't be too many options.
To my mind this way it would be easy and fast to try out different settings with shapers and then finetune manually as needed.
I tried to think of the easiest way of doing it, hoping you won't claim this one also to be "too complicated".
Now I have no idea what to say. That looks like you have problems with your audio card - simply, when you put there a plugin that does lots of CPU (or more like uses specific resources), the audio interface may pickup its bus frequency. For example, in my old computer my old mouse was doing noises! 
