The inclusion of the ability to compare workspaces in workbench as part of the git workflow is a really big step forward when it comes to including FME in the typical development workflow.
Another really helpful addition would be having the ability to either embed or link certain custom transformers via command line.
We work on a number of projects with often each contain several Custom Transformers - Each of which are maintained in separate Git repos. During development of the 'main' workspace these CustomTransformers are linked to the latest version.
When it comes time to releasing the new version of the workspace it is a manual task of opening up the workspace and embedding the transformers. The alternative option is to deliver the CustomTrasformers in addition to the workspace and have the end user install the CustomTransfomers before opening the workspace.
Being able to automatically embed select custom transformers would enable a proper build pipeline.