An earlier Q&A (What are Esri's new "ArcGIS for Professionals" and "ArcGIS Pro"?) provided some reassurance that ArcPy code would have re-use value with ArcGIS Pro:
ArcGIS Professional Extensibility. Here are our current thoughts about extensibility for ArcGIS Pro. You can write and run Python scripts in ArcGIS that call geoprocessing tools and use an exhaustive suite of scripting functions available in the ArcGIS Python API, ArcPy, to automate your GIS tasks.
However, it makes no mention of whether ArcGIS Pro will enable model building to automate workflows using a GUI that is either (equivalent to) the existing ModelBuilder or a major improvement on it to address previous enhancement requests from others and I.
Has anyone heard the road ahead for ModelBuilder (or at least model building) in ArcGIS Pro?