So I did a bit of a comparison WAC vs diablo line and something new, combining them both. Just flying the kite around no riding. 5 to 15knots .
WAC line has slightly more bar pressure, relaunch is great I think better than normal, turning is tighter, kite cambers more and has more lift, kite back stalls better, reverse landing is easier with the kite having a more laid down profile with less pull on the ground. Overall I think I prefer this to the diablo line.
Diablo line has lighter bar, more responsive turning but wider arc, less camber less lift, much worse relaunch than normal, harder to backstall. It's possible the harder backstall could give the perception this is better for downwind, but the camber performance aspect is significantly better on the WAC and should be better with better bar control.
Something like a kite on steroids. Really high bar pressure, really cambered, very high lift, responsive tight turns, ok relaunch not as bad as a diablo line alone. 12 knots my 6m was pulling very hard. I can definitely see people picking this option. If you just need extra lift to get you up on your hydrofoil this will do it.
Back to the diablo line I don't think there is any way it could not negatively affect reversing/relaunch. It puts CZ linked on a pulley so the balance point is going to be somewhere in the middle. Because of that the tow point will never be able to move close or onto Z maximizing lift backwards. But! If the kite was designed with C being further back and to a lesser extent but also Z as well the middle point would be further back too and reversing would be better.
With the WAC line I think B being further back and maybe C it will work better as well.