I'm testing filters that can't be placed as a filter mask. Is there any one of those filters that would be feasible as a filter mask any time soon as in possible?

What I'm looking at now:
- Color Transfer
- Wave
- Sobel
- Auto Contrast
- Small Tile
- Pixelate
- Wave

The last time I asked, I remember that Krita does not support multi-threaded filters as adjustment layer/mask. I'm going to assume that none of those are possible solely because of that reason. I'm going to assume that multi-threaded filter adjustment mask/layer might be possible way in the future, but nowhere near now.

And then, I'm looking at this in XML:
<stop bitdepth="U8" offset="0" alpha="1">
<RGB b="0.91764706373" g="0.90588235855" space="sRGB-elle-V2-srgbtrc.icc" r="0.91372549534"/>

So, it is possible that filters could work with other color space and depth? Like say, if I wanted L0 to L(insert max value) gradient, and it follows that in a linear step, this is possible? Doesn't look like I can do much about the precision issue and interpolation. It would nice to have more precise gradient, and that would enable more precise effects.

Right now, these filters seem to be 8-bit only
-Threshold
-Color to Alpha

So, I'm guessing right now, there might be a need for something like GEGL to solve these issue?