I agree that there is some limitation with 40mm being the widest lens for the Hy6.
True, I am not quite sure what their strategy is yet. Larger sensors are just as good as wider lenses in terms of FOV, and we have heard that the upcoming 35mm will cover 6x6, but none of this will pay off until there is a 645 or 6x6 sensor for the Hy6/AFi. (I know Leaf has that 56mm wide sensor but it's an odd ratio.) A 28mm lens on a Hasselblad, limited to 48x36mm sensors, is equivalent to 33mm on 645 so the 35mm will more or less even things up.
I personally don't think that sensors will be larger than 645 for many years, so a rotating 645 back would be a great match for the Hy6, BUT any new lenses should not have to cover full 6x6 - this adds unnecessary weight and cost and FOV limits. Perhaps Schneider/F&H will see the light and release some sort of 30mm lens which covers 645 only. I won't hold my breath though.
So my advice to Sinar/Jenoptik/F&H would be: get a 645 sensor out, preferably like the wonderful eSprit65 but with larger sensor, and get that 35mm lens to market. That should finally silence the critics.