I'm curious, what is your audience/goal for this? It's been my impression that most of the people on the Think Data Thursdays are oriented towards "What are techniques and/or views that I can use with Tableau today?" and not on thinking about what Tableau may or may not develop in the future. In the latter case, I wonder how useful a discussion would be without having one or more Tableau product/marketing folks on the line as well.
Personally, I'm not really looking for more chart types (though hierarchy and some basic network graphs would be nice), I'm more interested in being able to add more detail to existing charts (like in-cell time series aka sparklines, embedding charts in tooltips and annotations, etc.)
I did browsing all the groups &forums before posting here, and i choose TDT because contains "think" word. I accept that maybe is not exactly the place to have this type of conversation, more closed to a brain storming one.
Could you please suggest a different forum?
I think Viz Talk, or the regular forums. You could help jump start the conversation by making a list of Ideas that covered different visualizations, because other than cornering a Tableau developer or product manager that's a big way to get prospective features noticed for consideration.
Now information graphics needs to be attractive and innovation in addition to informative. There has to some additional stuff and user friendly interface. Simple yet very attractive.