In my experience your method is the only way to achieve what you are trying to do.
Your workaround today to delete the file is currently the best way to achieve what you are looking for. If you just want to add data, we do have append functionality. Enhancements to support schema changes is something we will look into incorporating in the future. We're constantly working on enhancing our TDE API functionality and appreciate your questions and feedback.
Tableau Software, Product Manager
Good day Ashley Jaschke
I have a suggestion for you as Product Manager, port .tde API to R Language. This task is not linked to any internal development dependency or other technical constrains.
I shall recommend to ask your skilled coders to use Rcpp framework (http://www.rcpp.org/) for seamless and fast integration.
The request is already posted in idea forum http://community.tableau.com/ideas/2831
On the same subject you could read: