we use it for topology optimization and also have interfaces that have edges.
We also use other programs where we would have to import a STEP, for example to check the function.
We are still testing the NX12 tools.
It's still not clear what your workflows are and how STEP would help them?
If you have a Convergent Body, then at least some of the faces are "facets", to make a simple explanation.
Those sorts of workflows are not typically supported by STEP, but usually use the formats that Ben mentioned.
They are useful for some workflows, but not all, so it's helpful to have more detail on your desired workflows and the end result you hope for.
I'm also interested in what "feedback" are you waiting for from Siemens and what channels you have used.
You've already had at least 2 replies in this thread from Siemens folks, so don't assume your queries are ignored :-)