I think while what I said initially about high G_e is true, it is also true that there are numerous practical issues related to flying very fast like Makani opted for. So I agree that it is maybe worthwhile looking into some less ambitious designs that are more feasible in practical terms.
I dont quite understand your calculations. If the kite has a G_e of 4, you must load it such that the sum G_e with power production «drag» force is G_e’ = \frac{4}{1 + 0.5} \approx 2.7. This allows you to calculate kite speed (around 1.5-2 times wind speed in practice perhaps, no more than 2.7 times windspeed). Next one may calculate how big the drag force of the power producing blades must be in this airspeed. My guess is that for optimum induction factor the blades must be fairly large.
If we eg. consider a AWE like this flying 2x the windspeed, the onboard blades will produce 4x the power compared to a ground based HAWT. This means the onboard blades must be half the diameter of the ground based HAWT.
Such calculations suggest that drag mode AWE works better at higher G_e even than 4.
I do think a glide number for a foil kite could approach 8. With a flying speed of 4x the wind speed, the diameter of the airborne blades would be 1/4 of the ground based windmill. And so on.
To take this to the ultimate conclusion, the blades you propose will be too heavy unless you also use kite blades for the airborne blades. Using something like @Rodread’s Daisy rather than a HAWT like blade should make it possible to increase swept area drastically onboard without a huge weight penalty. In theory of course. Handling should be disastrous