I've been toying with a bit of a rewrite of write.xlsx() which separates the building and saving process. Ideally, a (named) list with ... params could be passed to something like buildWorkbook() which would generate a Workbook object that can then be further modified before saving -- often something I personally find myself doing and could see a general utility. write.xlsx() would then essentially be shorthand for ...

wb <- buildWorkbook(data_list, ...)
saveWorkbook(wb, file)

... when finer edits would not be necessary.

The process of this would involve a better method of passing/matching parameters -- would would resolve issues like like #187 and wouldn't require additional edits when new params are added -- without changing the current use of write.xlsx()