When you put biblio.title in a notice, it doesn't include the subtitle. Including the subtitle is both good, and trickier than you'd expect as there's no column for it.
I plan to make a 'biblioitems.fulltitle' thing that will make a well-formatted title for notices.
Unfortunately, my plan has had to change. Leaving this here as a wishlist because I think it's a good idea.
Maybe the question to ask if 245 $b, etc. can be included in other places, not just for emails, but in Acquisitions and Cataloguing. It was one of the first things we noticed after migration- it is ever so inconvenient not being able to see the rest of the 245.
Bug 11529 will add columns for subtitle, part, number, medium and it should be easily possible to include them in notices then.