On a fully sheeted wing, you would be correct. However, what you're describing is nothing more than a "D" tube structure. Although it's strong and rigid, the rest of the wing is easy to remove the warp or twist from using heat and reshrinking the covering... to a certain degree.

If you were to build in a degree or two of washout, you would have a much better stalling plane that shouldn't fall off on one wing or the other. Figure out how much spacer would be needed to get that washout. Pin down the root of the wing and place that spacer under the rear of the tip rib while pinning down the front of the tip rib. Now apply the heat gun to the covering to get the wrinkles out and let cool. You probably will need to get rid of wrinkles in bottom too. Be judicious with the heat gun and make sure the upper covering doesn't reheat and return to it's old position.

Now do the same to the other half of the wing. Use an incidence meter to make sure both sides have equal washout and you should be alright. Just be careful on really hot days or keep your plane in the shade or it could return to it's old self or partly to it.

I've used this method twice in the past and it worked pretty well. Good luck.