The first steps were , in fact tried 70 years ago....and there is the rub. Steps work great.......................as long as that much of the bottom is in the water......so it is a question of speed. If you are dealing with a monohull, and a step is say 60" forward of the transom, then the step will break the running surface up and reduce friction..... if that much of the bottom is wet. The old boats pictured carried a lot of motor weight and ran very "wet" to begin with. That's why tunnel boats use them.....mostly in turns when the sponsons are sucked down...not in straight a ways.
If you can rock your vee back onto the last 12-18" of pad you are already going too fast for steps to give you a speed increase. That's why non-stepped Allisons are so competitive in outboard drag racing. However, in turns the monohulls lose rear end tractability with aerated (stepped) surfaces and either spin out or hook and barrel roll more frequently with all that junk on the bottom.
A cat tends to turn on the inside sponson walls and holds better in turns than a vee....but a non stepped cat will spin out less often then a stepped cat as well. It is not a question of absolutes but rather of degrees. My 28 Skater runs fastest when I am able to trim all of the steps out of the water, but before I gain too much attack angle and increase aerodynamic drag.
Mike, we did, in fact put steps on two 21 Shadows in 1981, a Sterndrive and an outboard, Both boats were identical grey, white and Navy blue and their photos graced our brochure that year. The steps were 1 and 1/2 " deep, and made the boats no faster....yet they were more slippery in turns. This is still true today.
As to the Wing Switzer, that design is not a true cat or tunnel but rather a four point HYDROPLANE. Hydros by design kiss off on the forward sponsons and carry the aft section completely clear of the water......and without skid fins they literally don't turn at all.