Just praise and some questions.

[xebialabs-community]

Just praise and some questions.

[ladamato]

Thanks for the feedback!
To answer your questions -
Technically, we can create a new variable programmatically when the release is run. However the usecase for which this plugin was designed requires that those variables exist ahead of time, at template creation time, so they can be used in various XL Release tasks. The variables can then be populated when the release is run.
Regarding the variable naming syntax, perhaps the reasoning is on less firm ground. As I recall, when we added xml processing, we decided to use the underscore rather than the slash notation used in XPATH (since this is not actually XPATH). We continued using the underscore notation when we added JSON processing so it would be consistent and would not be confused with true dot notation. Our path processing is very simplistic and doesn't implement all the features of XPATH or dot notation.
If these design decisions have caused issues in you specific usecase, please let us know. These plugins are often designed to solve a specific issue we have been presented with. Feedback from other users will help us make them more universally useful.
-Lynn