D800E and Moire - Any Problems...?

Given the fine, repeating patterns in alot of UW life, I'm wondering if moire would be a reason to not get the D800E...?

I can't answer your question from having used the D800E but for the last 6 months I've been using my D800 to photograph fabric in my studio. I had the same concern for both shooting the fabric and images underwater. I chose to go with the D800 to minimize post production editing. I use both Photoshop CS6 and Lightroom 4 for post production. Fabric is quite unique in that I almost always need to colour correct and balance, plus image sharpness has been really key and I don't really think that the fabric images have suffered in detail. I compared the D300 images with the same lighting, fabric and lens and the D800 was incredibly superior in colour saturation and sharpness. The only difference was that I had to move the camera closer to create the same perspective with the same lens. I'm not sure if this helps but with as many images that you may shoot underwater given the huge possibilities with virtually unlimited memory card space you might consider post production as a factor. Lightroom helps in that you can select one image, make the edits and then apply those same edits to all of the selected images in your library. I hope to house my D800 soon and I intend to use the camera underwater as much as in the studio.