Two strokes make less torque, but rev higher. The reason for that is they have a shorter power stroke than a four stroke with the same stroke, due to the exhaust port venting before the piston hits BDC. With a four stroke, you have valves controlling when things enter and exit the cylinder, so you get a longer power stroke.

That being said, the two strokes rev way higher, and make more HP. Those very valves that give a four stroke the longer power stroke and better torque also cap off it's RPM potential. HP is simply the output of an equation which factors in a constant, torque and RPM, so if you can rev higher you can make more power. The OS FS-26S-CX, for example, only makes 0.65HP or so. BUT, it makes way more torque than a comparable smallblock two stroke, so if you up the pinions appropriately, you can go faster. You can supercharge the four strokes if you want to recoup some of those losses. While that RB Innovations supercharger is of dubious use at best on two strokes, with a four stroke, it should boost power significantly.

Personally, I feel the only real reasons to fit a four stroke in a car are fuel economy, noise and engine life. Being four strokes, you can put mufflers on them without crippling them, they have steel sleeves and rings so they last forever compared to an ABC engine, and since they have half as many power strokes, they get roughly double the time per tank than a comparable two stroke. That's kinda why I want to get one for my CEN, if I'm honest. That thing flies with a two stroke but I think a four stroke would be better suited to it.
Rotaries are a bit of an oddball. OS does make one, displacing roughly 0.50ci and for use in aircraft, but from what I hear they suffer the same reliability problems their larger cousins suffer. Namely, the apex seals wear out pretty damn quick. The reason they aren't used in cars is twofold, IMO. One, their shape and the location of the output means they don't fit a chassis well, and two, cooling them in a car will prove to be a bit of a bother.