I’ve seen Tufte and learned a ton - the presentation was almost _too_ information dense (which is his intent). Curious why your experience was different.
But in general he had a lot of one off examples and interesting pictures, but without a solid and applicable theory behind them. He was an articulate speaker but I did not feel like I learned anything from the talk. I have also "read" his books but the only thing that I remember and make use of is the idea of information density on charts.