Is anyone else absolutely as bewildered as I am that there is no way to do this?!!
How can you offer <Data Update Time> only in a sheet's title--which is useful in such limited capacities.
Some of Tableau's misses can be very frustrating. Don't get me wrong, I love Tableau's Data Engine. Just when I try to do larger projects with Tableau, I get 85-90% there and then am absolutely stonewalled. Going further at that point requires so much creative thinking from a hack perspective, that it creates incredibly large inefficiencies when those creative-thinking resources could be much better spent on more strategic development.
I just wish some of my Tableau projects didn't require heavily modified hacks (JavaScrip API + thousands of lines of custom logic to get around Tableau's shortcomings) just to achieve basic level functionality that you would expect from a server-side API.
It seems like Tableau really doesn't put much emphasis on it's non-administrative API offerings, which is a disappointment.
Anyway, in the interim, I'd like to request that you make this <Data Update Time> feature available somewhere that one of your APIs can access it directly, or indirectly, such as through a calculated field. It would make managing projects with multiple workbooks and datasources much more easy from an end-user governance perspective--especially when some datasources are updated on different refresh cycles.