Rushnut wrote:

On topic, I really think that a datum for filters and an associated filters list would be the best solution.

Here's the problem with that: The datum has to be tied somehow to the object so that it can update the appearance, or it has to be read-only like overlays/underlays currently are, with all filters reapplied en masse. The latter would be fairly awful to work with, though no more awful than overlays/underlays are currently. The former would be radically difficult to work with.

Although even then, I have no idea how I'd handle filters that take secondary images as arguments.

Would we have any chance of being able to animate filters in and out for smooth transitions?

That would be one of my design goals. I think as long as the filter types and orders remain aligned, it would make sense to animate their parameters.