It would be helpful if a Step's (or stage's) matrix values could be access by a subsequent step/stage in the pipeline. (Perhaps: <+pipeline.stages.MyStage.spec.execution.steps.MyStep.Matrix...>)

This would allow the next step (eg MyNextStep) to dynamically interrogate specific instances of the matrix step. For example if MyStep has a matrix of [alpha,bravo,charlie], resulting in executed steps of MyStep_alpha, MyStep_bravo, and MyStep_charlie, then currently MyNextStep needs to either be hardcoded to read values from these steps or perform complex parsing of the entire pipeline file. However with this feature MyNextStep could read the matrix value directly.