I so love TBird. Best email program on the planet.
I run it in Windows, Mac, and Linux worlds.
And I love message filters.
The one deficiency in that functionality: the ability to export and import a set of message rules to/from a data file.
Lotsa folks have wanted this for a long time. I understand, though, the low level of programmer staffing on this vital project, and the many priorities already chewing up their time.
My own time is also deeply chewed up for the next year by lots of stuff, in and out of the progging world. But: if nobody else does this little goodness before then, I'll take it on myself. Been playing with code for 4+ decades, including a long Microsoft stint, and writing books that teach other folks how to code, so this'll be quite doable, though somehow I'm imagining the code base might be a bit twisted in this area, since it hasn't happened yet.
Anyways: just wanted to get this on the ideas list.
-- stanley krute