Two strokes would certainly be fun butt, like other engine options not offered, they’re both marginal in postwar production (early Saabs, some minicars in western Europe, the Trabis, some early Kei cars…) and a major rehaul - graphically and in the whole calculation system that’s behind it.
I certainly hope for that, one day, around Automation 6.0 I guess, since I have a taste for quirky engines, but there are many engine options that are either easier to implement and/or more significant in engine history before them.
If the devs ever branch out of Otto Cycle, Diesel has a much larger place in automotive history, Wankel would be much more of a fan service, and Atkinson+Hybridation would serve the modern era better.
I guess you could still tune your engine as “two-strokey” :
I found that my “Quasi Diesel” engines, while sadly not sounding like Diesels, fit the purpose well. Efficient, low-reving, torquey, reliable, but large and heavy engines are possible…
As en European, I’d be tempted to say than any american engine from the malaise era basically behaves like an european diesel engine - minus the efficiency
Also, bear in mind that offering more options would also deter from the game accessibility and balancing.
Sure, twin sparks, variable V angles (Ferrari has 65° and 180° V, VW 15°, the old Lancia were also very narrow, etc…), air-cooling, CVT, hybridation, flat-twins, the list is close to being endless, but there is already so much to explore with what we have…