I would posit that an "ultimate" visualization tool would allow me to exploratorily map aspects of my data to various aesthetic properties of the plot, such as size, color, shape, and transparency. I'd also expect to be able to get something reasonably close to publication quality straight out of the software without a whole bunch of tweaks.
I was hoping that this post would show me something about visualization workflow or extensions they'd written to ease some of the old pain points. As it is, they lead with a statement that is pretty laughable if we compare to ggplot2 or Tableau.