I remember my first few weeks working on MVS. The syprogs around me used JCL, assembler, and what seemed to be an arcane set of CLISTS to manage the system. Lucky for me, there was this new language on the scene called Rexx that allowed me to use skills I already had to build management routines. Like it did for many others in the industry, Rexx allowed me to grow my MVS skills and manage my environment without having to learn everything all at once.
Today, the language used to manage most platforms is Python. With Python being available on z/OS, a new generation of systems programmers can use existing skills to help them learn not only how to manage z/OS, but to create new methods for using and managing the platform. Python is going to introduce a whole new generation of sysprogs to z/OS.