I have an idea for using microsoft flow with sharepoint for mananaging project workflow in a manufacturing environment. It's hard to explain in only words but I'll do my best.
The workflow would have a page for each stage in a project's progress. For example, one page through the sales workflow, one for the engineering, one for the production, and one for installation and startup. In order to move a project from one stage to the next, a set of tasks/forms would need to be completed, which would shift the project to the next page's list. Each page would contain the tools needed to move the workflow along. This can come in the form of engineering details forms, production checksheets, or more. Documents that need approval (like those going to customers) could be routed automattically to the approving managers, and then notify the owner when it is approved to send. Etc. There's a lot more details I could write, but this should give the basic concept. Again, Sharepoint has pages for each stage of a workflow (engineer-to-order, per project); these pages host the projects in that stage of workflow, and the tools needed to move it to the next (process policies, work instructions, everything that is needed); and that data can be collected and overviewed in a final page to visualize everything in the workflow, bottlenecks, etc.
I think what is missing from the current flow capabilities, is the ability to string together say hundreds of these automated processes that check for completion, and move to the next, pausing for additional work to be completed. I also haven't seen flows that move items from one sharepoint list to another.
If you are having trouble understanding this workflow I'm envisioning, imagine a Kanban board (in que, in progress, done), that spans the entire workflow stages of a manufacturing company. Almost like 5-10 Kanbans stacked together, with increments managed by Flow.
I'm happy to discuss more with anyone who is interested, my email is firstname.lastname@example.org. I'm a mechanical engineer who has seen too much disfunction in manufacturing companies.