Maybe i missed something but is it correct that there is currently no way to change the source directory path?
I am currently trying to migrate my arduino projects to platformio and for me the best case would be to simply throw a platformio.ini file in the base directory of my projects and compile my projects with different source directories.
i also hate the arduino ide requirement that every source file of a project must be named like the project, what a buill ...

Being able to choose my folder and file naming means a lot to me :)