There is demand for having these parameters configurable:

• https://bitbucket.org/osrf/ariac/wiki/2018/developer_tips
• https://gist.github.com/plusk01/7b50443138a8d4b0ff742fa86b75c1e5
• https://answers.ros.org/question/11353/how-to-delay-escalation-to-sig-term-after-sending-sig-int-to-roslaunch/
• my own use-case, where I'm re-processing some bagfiles having a rosbag record --bz2 node in launch file, which doesn't finish saving the output bagfile in the 15 seconds time-frame after the source bag (with required=true) stops playing

Is it possible to submit a patch/MR that would add a roslaunch command-line option for this? I don't see any backwards-compatibility problems if we use the current values as defaults...