I don't see going back to the beginning, Intake over Exhaust, atmospheric, as a fix.
I have a basket of reed blocks/cages, and some lopped off intake ports to fit. Retrofitted plenty on 2 strokes.
GEM reed kits for early PP bikes were popular, and period testing backed up the restriction on top, without added porting. Boost ports, Boyesen ports, holed/arched piston skirts, etc
Modern mega-cages suffer very little. CF reeds are available in many thicknesses to tailor stiffness.
PP engines can be ported for very low speeds, several industrial applications, Briggs R-Tec, Robin/Wisconsin 125, etc. But, to do low and high, reeds are needed. One can have essentially 360 degree port timing, and let the reeds meter the one way flow.
In a 4t, meh. Honda used a tiny 4 petal unit from the CR80, and WB promptly created a replacement stuffer. Same with the more recent KTM, added farther back, for Euro standards. Just yanking the reeds and leaving the big rectangular duct kills low end, but replacing it with a round tube is a gain everywhere.
Aylor reeds for a Kaw triple are much smaller than previously accepted as needed, and still make big power.
But, apples & Aardvarks, in that the intake resonances are far different.
VVT via Rhodes lifters, seems underutilized.
Evolution of my case reed golf cart from 3 thin slots, to one Boyesen dual-stage, to an 8-petal sled cage.