Ok, I am a broken record
Having started using Edge Workflows aggressively as I have said in the past, the inability to call other workflows makes me hesitate to move forward too much.
Implementing complex logic, that needs to be used in multiple parts (or nodes with lots of configuration) is problematic and error prone, as a small change requires editing potentially other nodes.
The breaks DRY.
So for me calling other workflows (and ideally having the custom nodes) available in Edge Workflows are probably the main barrier preventing me from going all in on Edge Workflows.