Everyone has a different criteria for what they are looking for in winery to visit.
My preferences is for those that offer seating, even some at the tasting bar. That is a hard call for the winery, as they do not want people sitting there forever as though it was a real bar bar. That said, whether rustic or elegant, the more physically comfortable the experience, the more people with buy and write a good review.
Also, wineries that offer tiered experiences, from a simple flight of the larger production wines to exclusive areas and tasting for those in the wine club or paying for a premier experience, are my favorite.
A gift area as well as some food options are common these days, and the more imaginative the better.
Photo is from the Trinchero family in Napa Valley, their tasting venue of their limited-production, estate-grown wines.