Is there a plan to allow publishing of services from ArcGIS Pro directly to ArcGIS Server?
No. The introduction of ArcGIS Enterprise, which integrates Portal for ArcGIS, signifies a shift from the client-server pattern to a Web GIS pattern that takes full advantage of the geoinformation model. A key design concept of Web GIS systems – such as ArcGIS Online or ArcGIS Enterprise - is organizing a collection of items in a portal. Accessing this portal from any device, anywhere, at any time allows you to use, create, and share geographic information throughout your organization, the community, and openly on the web. This information includes items like maps, scenes, layers, analytics, and apps. ArcGIS Server on its own is not capable of integrating into this model without the additional capabilities and content management functionality provided through a portal. For many of today’s advanced GIS service types, including vector tile layers, feature layers, and more, the service by itself does not contain all the information used to style or describe the results. Instead some of this information is part of the corresponding portal item, which gives more flexibility for modifying or changing content on-the-fly instead of going through the full publishing workflow.
ArcGIS Server is a crucial component of ArcGIS Enterprise and can be thought of as the engine behind the scenes, but it does not stand alone in the modern GIS.
