Are you confirming that these fields no longer support parameters being passed, then, when the previous post-capture script field did?
I would consider it perfectly adequate to be able to pass a single string parameter; as you say, it's possible to pack an arbitrary number of fields/variables into a structure like JSON that's passed this way if needed, and if you're writing the receiving script yourself you can build it to decode whatever is passed pretty easily. This would only be slightly less convenient for people trying to trigger a pre-built command provided by somebody else without having to write their own wrapper, but if it's easier to support a single parameter than an arbitrary number then that wouldn't be a showstopper
In a previous version of Ekos, I had been using the post-capture script with a command like the following:
2021-05-16T01:33:43 Executing post capture script rts_shutter.py 120 2021-05-16T01:33:43 execvp: No such file or directory 2021-05-16T01:33:43 Post capture script finished with code -1.