In addition to the #productfeedback that is mentioned here:
I think it would be very helpful to be able to import data directly into existing Sections. Currently, tasks can only be mapped to Sections if the Sections are created within the same import file. If a task was imported within a Section that already exists, a duplicate Section is created upon the completion of the import. Much like mapping to existing Organization’s Custom Fields, it would be great if existing Sections were also acknowledged through the CSV import process.
One specific and widespread use case in our business is to stack tasks within Sections. Not having to relocate all tasks that get created under a duplicate Section would certainly make the import a much more seamless process.