navigating the view port in object mode and edit mode is good. in sculpt mode, it is easy getting used to. as it rotate the view port around the last modified spot. however, it is weird when it comes to vertex paint mode and weight paint mode, as it does not rotate around the last modified spot, instead the object median center. often time, it is hard to focus back to the painting area, as obj becomes complex.
suggestion: change it to the same way navigating the 3d view port in sculpt mode.
It seems there is a bug in 2.8, “Rotate Around Selection” preference is not working in the Vertex/Weight Paint modes. In 2.79, it works the same way in all modes. Just create a bug report.
thanks for the reply.
just downloaded and tested a newer version of 2.79, it is as you said.