Based on your suggestions, I've introduced AbstractXlsView, AbstractXlsxView and AbstractXlsxStreamingView variants, designed to work as closely as possible with POI 3.8+'s arrangements. The traditional (pre POI 3.5) AbstractExcelView has been marked as deprecated, just like AbstractJExcelView already is.
I went with separate classes (in a hierarchy) primarily for minimum dependencies imposed, i.e. no poi-ooxml dependency needed when just using HSSF. As a side benefit, the content type can also be determined in the constructor then, and the SXSSFWorkbook.dispose call can be applied in a cleaner fashion.
This will be available in the upcoming 4.2 snapshot. Feel free to give it a try...