Sorry for my confusion but let me get this clear, your post title states "NAV" but you're referring to the little LCD display screen between the temp gauge and the fuel gauge?
The turn by turn and fuel economy is like what "awesomez" said, if you have NAV and you press info, it toggles and shows all that.
Are you implying that you want something more that could show the Nav turn by turn direction inside that LCD display too? Kinda like what the Lexus RX has as a projected image to the windshield? (except it can be put into that little LCD screen? That's a cool idea, but I think it's a little too redundant if you already have it showing under the center console display.
I don't know if this is any different on the '09 model since I got the '10 model and they did a NAV upgrade, but it think what they have showing in the center console is sufficient already and is very visible.
But to your concern about having an upgradable firmware, I'm totally on board with that idea. They should have a firmware that can make our Navs be like the GT-R. More performance readouts
I do have one huge complain though about Nissan's NAV....it's too freaking SLOW!!!! god dang it's one of the slowest factory NAV's I've ever used. I'd press a button and i'd get no response for more than 20 seconds. How is that even allowed?