I moved from the Nikon D300 underwater to the D800 just over a year ago.
For the D300 I used the Tokina 10-17 plus Nikkors 60 and 105. I had the Nikkor 10.5 but used it rarely after buying the Tokina. I now use the Sigma 15mm, and the Nikkors 16-35mm (with a +2 diopter) and 105mm. Like Alex, I am now finding that I could do most trips with just the Sigma 15mm and the Nikkor 105mm.
I have found two other issues with the switch to FX (other than losing the Tokina): the transport weight/bulk of the equipment; and the need, again as Alex highlights of a bigger dome.
I've just got back from 4 weeks (woohoo!) diving in the Caribbean where I took my Subal housing, two D800 bodies, the three lenses I use u/w and one topside lens. I had two ports (Subals for the 105mm and the 230 dome) plus 2 Inon strobes and all the usual bits and bobs. I reckon I had something like 25kgs of packed photo gear - and, most noticeably, could not pack the 230 dome port in my Pelican cabin-size roller box or even in my dive bag as it then became 27kgs. And, believe me, my clothes and non-dive stuff weighed about 500gms! And I was travelling light-light with dive gear too.
So bottom line, FX lenses and bodies - at least at the D800 level - are significantly heavier and bulkier than DX.
I started with using the Subal DP-FE domeport for my Nikkor 16-35 but there is no doubt that edge sharpness was lacking and I have now switched to the DP-230. Cost aside (ouch!), I was still taken aback by the sheer increase in size of the port compared to the DP-FE. Hard to believe that an extra inch of glass diameter makes such a difference. But it does. I'm now carrying that port as yet another carry-on in a padded cool bag.
So, those, for me, have been the negatives and something, I'd suggest anyone planning on moving from DX to FX, should bear in mind.
And the positives? Wow: the image quality. I was always pretty happy with the D300 especially with macro - but the D800 is sharper, more cropable - but, as others have found with the D800 requires greater care.
Sorry, a lot of this has not really answered your basic question but I did think it worth highlighting. So, no, I don't miss the Tokina now. And the Sigma 15mm and the Nikkor 105mm are the go-to lenses. But I do miss the lighter weight of the DX system.....