I think the issue of glass V. acrylic has been going on since the beginning of U/W photography and you will find pros and cons. to both with more of the "pro or higher end shooters in the glass camp. Any of these ports on the Nauticam housing can make a very small package for fisheye photography. I use the ZEN Underwater 100mm optical glass port which is actually a Subal type III 100m glass port on a Subal to Nauticam Mini adapter. The upside here is that you can also mount other type III ports to the adapter. I also use the ZEN 100mm with my Olympus 12mm F/2 lens. For over/under I like a bigger port but you can get by in very calm water. I did a review for the ZEN port in a back issue of uwpmag.com. This is one of my configurations for shooting the 8mm fisheye.
The M43 cameras have a 4:3 aspect ratio sensor (not a 3:2 aspect ratio like 35mm or ASP-C sensors) so with the Olympus 60mm macro lens at life-size or 1:1 the image size is actually 17.3 X 13mm. Images of 35mm at life-size (1:1) and the 60mm macro at life-size (1:1).
I think it is a bit early to speculate regarding current ports since no specs on the lens size have been released yet. It does appear that the lens is smaller than the 12-40 which fits the Nauticam and other housings. The issue then becomes the optimal extension for the port to get the best results.
Regarding the quality of this Olympus "pro" zoom lens I own both the Olympus 12-40 "pro" zoom and the 40-150mm "pro" zooms and they are the best zoom lenses I have ever used on M43 cameras. The many reviews by well respected sites support my findings . I would expect that the 7-14 F/2.8 will meet the same high standards, but until well tested we will not know for sure. If you are a first time buyer for the 7-14mm zoom I am sure that the Olympus lens will prover the better choice over the Panasonic 7-14. However if you already own the Pana 7-14 and a matching port making the switch may be a different choice V. the cost. The Pana 7-14 is already an excellent lens, again according to others reviews. Same for the Panasonic 8mm F/3.5 fisheye, an excellent lens which can be used with a very small dome ports. If you already own the Pana 8mm and port making the switch may also be an even more difficult choice of cost V. gain. Still quite early to know if the Olympus 8mm F/1.8 fisheye is even real and if the spec's especially the F/1.8 part are at all accurate. I have found 43rumors to be flat wrong so many times that I would rather just wait for the real Olympus press release which has already been made for the 7-14mm without many details.
You should be able to find a series of threads on this issue here and in the Olympus section of Scubaboard. Regarding the issue of a flat port you have several choices. The first port choice is the most expensive Nauticam choice which includes the rather complex gear that allows the 12-50 lens to be locked in the 43mm "macro" mode. This is NOT a true 1:1 macro, for that you need the 60mm macro lens. Regarding zooming the 12-50 you have the choice of a power zoom like the Nauticam zoom/macro gear or a manual zoom gear like the after market gears from Deepshot and several others. The aftermarket gears are around $100.00US and only zoom between 12 and 50mm they do not allow you to lock in the 43mm macro function. Next you have the ability to power zoom between 12 and 50mm (nothing in between) with an in camera function accessed through the up/down arrows.
So the choice is 12-50 zoom and $800.00US Nauticam port to get 43mm "macro" or about $800.00 to get the $300.00 Nauticam 65 port and the 60mm lens for your true1:1 macro needs. The 60 macro has significantly better image quality than the 43mm function on the 12-50. If you use the 50mm end of the 12-50 and a +10 closeup lens you will get about the same magnification as the 43mm function.
The you have the choice of the 9-18 and 7-14 lenses. If you own on of these lenses with the detected port along with the 60 macro you may never use the 12-50 zoom again, that is the case with me. I do use the 12-40mm zoom from time to time but it is a much more expensive lens.
Using the 12-50 or the 60mm macro behind a dome port works but be aware that you will gain wider angle of view on the wide end of the lens (12-50) and loose magnification at 50mm and 60mm with both lenses.
Regarding the manual focus gear for the 60mm macro, I have one and I would say it has been used for well less than 1% of all of the U/W images I have taken. The AF with this lens is excellent and when used with a focusing light manual focus is not really all that useful.
The attached image was taken with the 60mm macro and SAGA +15 closeup lens using auto focus.