It would be nice to have them designed with watercooling in mind but I very much doubt this will happen unless one of "us" can produce it, they, (psu companies), would be horrified at the thought of us watercooling their products
My point is not really about it being easier to water cool but more that they really are not progressing or improving the PSU, yes the Antec has some nice features but I also want to see Design & Build quality.........not one PSU I've seen yet approaches this.
The only radically different one was a fanless unit that would have been a brilliant concept for water cooling. Unfortunately it was lacking in 12v amps, (probably due to it's makers fanless passive nature). I'm guessing this wouldn't have been such a design problem if it were water-cooled. Either way just look at how much neater the layout can be when you throw away the old design concepts and start with a fresh piece of paper.
data sheet:-
http://www.rsg-electronic.de/en/datenblatt/rcp300w.pdf