feMergeNode opacity?

feFlood comes with a handy little thing:  flood-opacity.

 

As I was playing a bit with feOffset at
http://cs.sru.edu/~ddailey/svg/feOffset2.svg  I went looking for a way to
make an feOffset partly transparent (like offset-opacity) - of course there
is always feColorMatrix, but it isn't the most intuitive of things for some
authors I suspect. So that sets the stage for the question, if we have
flood-opacity (which seems pretty focused in purpose) why not a way to make
stages of a filter chain transparent like say an attribute that could be
attached to any  primitive (or at least to feImage, feFlood, feOffset, or
any mergeNode)?

 

It might be a bit frilly, since we do have feColorMatrix, I suppose - and we
could always lump n merge nodes into n-1 feComposite pairs and use
mode=arithmetic (ick!).

 

Cheers

David