I have noticed that you often get warnings in the print preflight tab, that aren't valid. I get warnings of low res bitmaps, under 96 dpi (ppi should also be the appropriate unit here) when in reality the resolution is over 350 ppi. Why?
Also when you use facing pages and you have an object that stretches over the whole spread, you get this warning if the paper size isn't big enough for 2 pages – even if you only intend to print one page on each paper. This could be solved by having an option to crop the print at the page border, and not print every object that falls inside the page boundary. This could also be handy in other respects.