Well the Beneteau First series are still using syms and doing quite well. The First 40 took 2nd and 3rd corrected in Sydney-Hobart
While I am not arguing that asyms aren't great, I think getting run over down wind is a bit more of a function of our tubby hull that is better going upwind than down than the asym. The flying tiger is a planing hull so of course it is going to walk past us downwind. An olson 30 and Hobie 33 are also going to walk right past us like we are standing still with the symmetrical kites as well.
While it is undersized in the light stuff, our boats are heavy air queens so I don't feel I want a bigger kite when the wind gets up. Try as we might, without honkin waves this hull doesn't want to break free and a bigger kite just makes me think that hole in the water will get deeper and put a lot of stress on the rigging for little speed gain. This may be different for the asym though because of it's more efficient shape.
I am looking forward to seeing the final product though!! It will definitely be cool!