Do you agree that Kradschützen as a unit type should be added to the game?
Kradschützen are in an odd niche: they were primarily used as recon troops, but were fielded in battalion strength. Or, sometimes they were: German division organization was hardly as standardized as this game indicates, especially among the Panzer and motorized divisions where the motorcycle troops most often appeared.
But if the game has armored cars and bicycle units, I don't see why it can't have motorcycle units.
Does adding motorcycles add functionality, or just a bit of chrome? Bicycles, armored cars, and camels make slight variations to gameplay -- variations so slight that remarkably few players use them. What would change with motorcycles? Genuine question, since they would seem to function exactly the same as motorized infantry or motorized recon at the level of gameplay HOI4 tries to represent.
Maybe, rather than making another unit type to clutter the division design UI, countries that fielded lots of motorcycle troops (Germany, Italy*, possibly others) could get a modifier to their motorized recon support companies. Maybe a national spirit, unlocked by a short (35 day?) national focus, something to the effect of "Standardize the Recon Battalions" that gives whatever effect motorcycles are supposed to have. Change the motorized recon company icon to an armed motorcycle, at least.
*Italy fielded "cyclist" battalions with their Bersaglieri formations, which were either bicycle- or motorcycle-equipped, depending on the time period and also what was available. I'd argue that the Bersaglieri were more significant to the Italian army than the Kradschützen were to the Germans, and that therefore they should be able to use bicycle troops as well (and probably start with a few in 1936). But the Bersaglieri will probably need to wait on the highly anticipated Italy rework/DLC/expansion. Maybe that's the place to put motorcycle troops in general.
And the Jeep could be represented by giving the USA a national focus somewhere in the industrial tree, something like "Standardize on the Willys Design." Make motorized 10% cheaper.