At the moment I am shooting UW with a canon 5Dmk ii + EF15mm in an Ikelite housing with handles. I use both the Ikelite 8" domeport and a 5" Underwater Camera Stuff dome. I have strobes, but often travel without them when freediving. Still I find this set up to be bulky and heavy, especially as I often carry more kit for land photography in addition to my UW stuff.
In terms of image quality I am actually happy with this 10 year old technology, it serves me well.
So I wonder if there are any more modern set ups that can match the 5D mkii image quality BUT does so with a significantly reduced size and weight?
(Wide angle is my only interest, no need for macro etc. )