I'm using Scribus to aggregate lots of PDF files into one document.
When I'm loading a large document with lots of embedded PDFs, there is a long delay while Scribus is generating the previews with Ghostscript. Drumming my fingers while this was happening I've been thinking, "This delay is unnecessary. Why can't Scribus cache these previews?". This is more of a feature request than a bug. Is the bug tracker the appropriate place for such a request? It would speed up my workflow a lot, if my files loaded quickly.
This next thing is more of a tip:
Having lots of embedded PDFs, the PDFs exported from Scribus are very large because of duplicate fonts. I've found that using pdftk's compress command remedies this.
http://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/This is a tiny program. Could Scribus include it in a manner similar to Ghostscript? It's GPL v2.