Ironic this thread should appear the day after Core launched their X-Lite which is a kite deliberately built with light weight in mind for foiling. Personally I've always been more in favour of build strength and quality over light weight and was happy enough that only kites 15 and over were built lighter, but that was then and this is now and the Soft build Foil kites have been gaining market share of late amongst the hydrofoiling community, we've even had beginner foilers having to perform the swim of shame with their twisted up dish rag trailing behind them on our beach, so for me it's good news. Without going all PMU on you soft cell foil kites are not good news in the hands of the inexperienced, a light built pumped kite will hunt the shifts better than a foil everytime without twisting a wing tip or inverting, so in that role, I think there's a good reason for light build.
Wether that light build can be light enough, only time will tell, but certainly for the recreational foil market I think they're a good thing, should they be built down to 4,5,6,7,8 mtr? Can't say I know enough about hydrofoiling to really comment with any veracity but Core have done it and spent a lot of time and effort, not to mention ball freezing mid winter swims by the designer, so I'm minded that they'll be good kites.
They haven't just stopped at the kite, the speed sailors amongst us have been pressing for thinnner lighter bridles for some time and they now have their wish and 300kg thinner liros kite lines with a lighter carbon bar to complement it, so wether there's a market for it or not they have committed.
OR have a new cloth with a stupid name, which will be interesting to watch the development of, if it's anything like Cuben these days, it could be as durable if not more so than Dacron or Teijin, I once built a 9.5 mtr racing sailboard sail from Cuben Fibre and that came in under 2 kgs with 5 battens and 2 cams and is still going strong 8 years later so these new materials are definitely worth watching once they iron out the initial wrinkles as Cuben eventually did.
Time will tell, but for straight up twintip and surf board high wind bashing, I'm still with build it to last and to hell with the weight.