The problem (well, at least for me) with the new-style IPTC screen is having all the fields in one long list makes it harder to visually check them all very quickly, and sometimes requires scrolling. With the old "classic" style you could easy scan all the fields with your eye quickly.
A possible solution, assuming you see this as a problem which I do but I'm aware others don't, would simply be to allow (optionally) the new-style IPTC dialog to be in two columns like the classic one, thus allowing us to "recreate" something similar to the Classic style. Just my 2c....