Hi,
I presented both the gradient banding and the filter artifacts problems at the joint CSS/SVG working group meeting in Sydney.
For the gradient banding problem, I asked if we could specify a dithering algorithm. The reception to the idea seemed good. It was suggested that I propose a method and syntax to the CSS working group. I'll do that in the future.
For the filter artifact problem, I proposed that filters should be evaluated using floats internally. Dean Jackson (Apple), one of the Filter spec editors is going to look into it.
I noticed that the filter artifacts with both Firefox and Chrome are less visible that with Inkscape. It looks like they are doing some kind of blending or dithering. That is something we could investigate. I know that applying a small amount of blur at the end helps quite a bit.
Tav