[rmattes]

catkin packages are just CMake projects, and you can use find_package to discover them without making your module into a catkin package. I've written a few drivers this way without any problems (using existing message definitions.) For example: https://bitbucket.org/richmattes/si7021-sensor/src/master/CM...

Lack of QOS (and many other things) are definitely a drawback of ROS. ROS 2 is built on top of DDS, which replaces ROS 1's bespoke messaging/transport and has a robust set of tune-able QOS parameters.