Surely it's possible to have a full alpha mask, such that 50% alpha means "push the diffusion process towards this value, but don't force it to generate this value".
You'd effectively be trying to do a pixel-by-pixel diffusion strength parameter, which I'm not sure has a coherent interpretation to the algorithm (because it's currently a scalar applied to the run settings).
the "alpha" is already built into the tooling and specified independent of the mask. IE. the stable diffusion inpainting takes hints from what you leave and "decides" what to keep
Surely it's possible to have a full alpha mask, such that 50% alpha means "push the diffusion process towards this value, but don't force it to generate this value".