Finally, I have been able to do some major feature editons. Now the development branch somewhat gets off. See the change log for rsyslog 1.10.0 to see what I mean ;)
I have to admit that creating this release was more effort than I initially estimated. While I was right that the base design allowed neat integration of the new filtering, a lot of infrastructure (counted strings, parser, …) had to be added. Of course, these additions will help in the future, too. But as I said… it took much longer than expected. I ended up adding 1,000 lines of code and also modifying others. So roughly about 1/6th to 1/7th of the project needed to be changed to make this feature a reality…