It might, but I think engineering plants to be drought resistant is still a long way off. There’s more to going from C3 to C4 than just stomatal function, like the typical Kranz anatomy of a C4 plant and the extra biochemical steps in their carbon fixation. Then again, some common crops (like corn) are already C4 plants, so it could be possible to make them even more drought resistant. I just don’t know how they’ll ever improve the yield of crops under drought stress, even if they can survive it.