This is a bug we noticed today already and a fix is in the works.
I shared the idea of selecting posts to print or export internally. No idea of if or when we will work on this but that something should be done is on our radar.
The print stylesheet not looking clean and attractive is a longstanding issue and I’d love to see it addressed!
IMNSHO, the stylesheet should be in the same font as the site, not times new roman, and include some site branding, at least the site name and logo if it exists, and the topic permalink and timestamp. Layout should be centered and efficiently use the space on the page but still have decent margins for readability.
Another related feature request that came up during the webinar yesterday that I found interesting was a bulk action option to select a few posts and export them. That could be incredibly valuable and is maybe a better alternative to adding a print or export button to the post menu or post admin wrench.
Hitting Ctrl-P would always be available to print the whole topic.