There are currently no immediate plans to offer a visual C# .Net Assembly feature in PB. The .Net Assembly feature scheduled for PB 2018 will be for non-visual use only. The current road-map for PB 2019 is also to focus more of the UI and Cloud feature sets.
If you consider this to be of prime importance to you & your organization, please let us know by emailing your suggestion to email@example.com.
Regards ... Chris Pollach
Appeon: Director, Developer Relations