Our stairs are now going to be completely within the addition, starting from the basement and going all the way up the attic (no more pull-down stairs!), including a landing on the driveway which will be the main daily entrance for our family. This also solved the issue of having a direct basement entrance from the outside which was important because Jim has a wood shop down there (his new one will be MUCH bigger!) and a 5th bedroom some day.
Another advantage is that our current third bedroom (former office, now a nursery), is very small because the stairs go "through" that room now. Ironically, that room has the best closets in the house (yes, 2 closets in a tiny room). But, now that the stairs will be moved, that room will become a good-sized bedroom which would be able to accomodate a full-size bed which is not possible now.