Just started looking at your work-in-progress and you are absolutely on track with what I think we should provide for this first stage of the WRFmet package. We can describe the initial functionality as:
Ability to ingest single-tilmestep local WRF output as 'raster' objects
Ability to create simple plots of WRF fields.
Ability to create ggplot static images by layering in any order: raster (from WRF or BlueSky or elsewhere); vector field (from U, V rasterBrick); spatial polygons; spatial points
Example "articles" demonstrating how to do this with WRF output, BlueSky runs; MazamaSpatialUtils datasets; PWFSLSmoke monitor data
Ability to create ggplot static images by layering in any order:
Maybe something like this? :