The historic problem with combat kits has always been that the models are so easy to build that most people just buy the wood and scratch-build them.
So I would advise kit makers to concentrate on taper-wings and other "hard-to-copy" designs that would justify the expense of a kit.
The Scalpel, designed by Chuck Rudner is a good example. It's a compromise between an Nemesis and a Bosta. As explained by a noted aeronautical engineer, the Bosta is 100% aerodynamically efficient, but almost impossible to build without being weak or overweight. The Nemesis is only 90% efficient, but easy to build. The Scalpel is 98% efficient, and once the ribs are cut, almost as easy to assemble as a Nemesis.
For those who haven't seen them, the Bosta is a true elliptical wing, the Nemesis is a rectangle, and the Scalpel is a triple-taper that approximates an ellipse. In reality, a combat plane can overcome the slight loss in efficiency by carrying a little more wing area.
I'm not an aeronautical engineer, but I play one on The Internet.