This might sound like a Yogi Berra-ism, but coupled flaps work best on planes that don't need them. For a model that displayed the snap bad enough to make me not want to fly it, or to make me be sure to always bring a Hefty bag out to the field....a couple things could be done.
First, build a wing with less radical tapers and sneak in some extra wing area.
Second, get rid of all hardware and onboard equipment that is heavier than it needs to be. Anyone with a militant attitude and some money to spend on downsized gear can find ways to dump weight.
This is the side of the hobby that can be fun and interesting if you are up to it.