I use the 16-35 with the Nauticam 230mm dome without a diopter. The problem with diopters is that they narrow the angle of view, and the 16-35 never seems wide enough anyway. (I moved from the Tokina 10-17 on a D7000 to the D800) And diopters are seldom made with the care and expense of native lenses. (I use B&W ones if I have to use them at all.) It always seems that my corners don't look as sharp as Alex Mustard's, but that may be because he knows where to focus to include the corners in the depth of focus, whereas it's all a blur to me and I use AF and hope for the best.
With the D800 I don't need the zoom range (you can crop a 35 out of a 16 file and still have an acceptable picture) but I tried Tobi Bernhard's 14mm 2.8 in Tonga last year and it didn't make me want to buy one; the corners were not great.
If you don't need high ISO particularly, I think the loss of the 10-17 is a high price to pay for 36MP files from the D800. Much as I like the ability to crop the shit out of them. And of course you can use a much smaller dome with the 10-17...
