IN 4.5 we had a OpenWFE workflow, where the customers were able to have Emials send by the single steps very simply. All they had to do was uncomment a part in the workflow definition.

I'm aware that JBPM workflow is much more powerful, but also less flexible as it needs to be compiled and so on.

But the simple use case "sending an EMail" is so widely common, that it can't be that every client needs to create their own workflow implementation just to sent a email.
It just sending an email, and almost everybody would like to have/use this.

I am aware of this:
https://academy.magnolia-cms.com/display/MA/M3+Custom+workflows+in+5.3+plus
But its not really helping. T mail addresses to use are simply coded in the Java code, not a real help for a real use case in a project.
Usually the ones triggering a workflow and the once getting it assign should receive a email, and not a hardcoded mail in the code.

Its a big time loss for customers to implement it by them selves, for such a simple use case that was possible within minutes in the past.

Suggestion:
Please investigate if there can't be provided a simple solution, where you can configure where to send mails to. So that a workflow step can use this config in a generic way, just to send a email within a workflow step.
Just the simple use case:
The triggering person of a workflow can get a mail.
The group and|or person that gets the workflow's human task assigned to gets a e-mail