On the newer OS's, the upper area only takes up about 1/3 instead of about 1/2.
Not sure what impact any OS should have on this issue -> it's all a matter of screen resolution. On a Win 7 system here with a 1366x786 notebook about half of the screen real estate is occupied by toolbars, mixer and stuff. On bigger screens it's less of course. The bigger the screen the better it looks.
PG representatives promised work in progress with respect to swapping toolbars and customzing the ordering of buttons.
No promises as of now with respect to providing more real estate for the chord chart window in case of smaller notebook screens, say. No promise as of yet to make the mixer optional in order to free space for shifting toolbars e.g. or to provide an option to go with the old UI style.
Guess we just need to see what options PG will eventually be providing.