If you already have the 85 1.4D would you trade 'down' for the 1.8G + cash for other lenses?
Mike, firstly on a completely different note, looking at the colour photos taken in the 1940's the colour was very warm compared to today, In researching glass types it was interesting to read that they used a radio active ingredient that had a similar effect to an orange filter, I always wondered why those photos looked so different yet strangely pleasant.
I think the 85 1.8g could have been even better if Nikon gave it 9 round blades instead of 7 Round like the 1.4D &G. I like the 9 straight blades on the old 80-200 2.8 ED. The Bokeh on that lens is very good though not as good as the 85 1.4d. Also the weight and close focus issues are a pain on the zoom, despite having the lightest version, though it introduced me to using the 80mm focal length, and enjoying it.
I think there is too much emphasis on sharpness, in the forums, If I wanted to do technical reference photography I would be more concerned, but sharpness can be the enemy of creativity, like the post from a pro that had the 1.4G and said the sharpness was unrelenting. It also reminds me of the photographer that the client refused to pay because she could see every wrinkle and he made her look ten years older, I don't like being photographed and not many people do. But I like some sharpness in the face and the 1.4D just hits the spot.
Talking of creativity I like painting like portraits and even landscapes, because they can express the emotion of the scene and direct the viewers eye. I hate clinical reproduction unless there is good reason for overly fine detail.
If you look at the great painters they used softness and light also sharpness at specific points to convey the moment in a unique way. This is what makes the 1.4D so good, in that there are so many choices between very soft and very sharp by altering distance and F-stop. Also it renders a very painting like background that is simply divine, and each time it is different, but gorgeous.
The other thing is that MTF charts will only tell you so much, as they are of a flat image and in the real 3D world a lens can look sharper.
The D800 as you said is capable of enormous sharpness, but what I am also learning is the importance of contrast in lenses which is not the same thing.