Unfortunately, there's no height for traditional USB ports! If you look at the photos, the 3.5mm jack is just barely fitting. USB-A is ~4.5mm tall, while USB-C is 2.5mm tall.

Compare these images:

15" new: http://images.apple.com/v/macbook-pro/j/images/overview/thun...

15" old: http://www5.pcmag.com/media/images/483214-apple-macbook-pro-...

I don't really need a laptop to be so thin, but it's a defining feature for Apple's "premium" feel.