Famously derided in the seminal work "The visual display of quantitative information". There they give the thought experiment: weigh the ink on your page devoted to data points, compare it to the entire rest of the ink. You want the largest ratio possible.
which relates to a strong preference to use whitespace as a tool for visual organization. If you could separate two areas of the plot by drawing a line with them, Tufte would have you use whitespace instead.
Tufte certainly loves complex charts based on complex data, drawn as economically as possible. He'd also recognize that there's a time for a simple chart based on simple data and that such a chart should be as simple as possible: if you want to make a bar chart with Excel with the last 12 quarters of revenue for your business for instance he'd accept that, but insist that you turn off as much chartjunk as you can.
