At the moment, opening a PDF file with LibreOffice necessarily opens it in LO Draw. This is often appropriate, but not always: A (non-hybrid) PDF exported from LO Writer or Microsoft Word, or generated using a TeX engine for an article or report - should be imported as a word-processor document; a PDF exported from LO Impress or MS Powerpoint, or generated by (LaTeX) with the beamer package should be imported as a presentation. This bug is not about the ability to detect which LO app should open the PDF, but for the more fundamental ability to actually perform the import. It should be stressed that this ability would be quite useful even if the import of stylistic features is partial and incomplete, as the LO user would at least have a Writer document with the relevant text in order (as opposed to innumerable disparate textboxes in Draw); or a presentation with the right slides, albeit perhaps not very beautifully formatted.
This is already provided crossplatform. Use os/DE provided file manager and identify the PDF to be imported. Then select the filter to be used. Each LO module has its own import filter for PDF. "PDF - Portable Document Format (Writer) (*.pdf)" "PDF - Portable Document Format (Impress) (*.pdf)" "PDF - Portable Document Format (Draw) (*.pdf)" Draw of course is the default import filter.
I'm pleasantly surprised!