Do you think this could be solved by giving all minors one free technology option? Obviously limit it so they don't get something ridiculous like nuclear weapons.
Presumably Finland and other Scandinavian countries did get the tech "free" at the start of the game. The problem with HOI3 was that the majors could research every tech, so SOV could get the tech and FIN would have no advantage in the Winter War.
Personally, I think MTN is perfectly good for representing ski troops. They are not just ordinary infantry with parkas, and a pair of skis. Their other equipment and tactics are based around operating in a harsh environment. Remember we are talking about a Division, not a platoon of ski troops. What artillery, mortars, heavy machine guns did the FIN forces use - were these light to take advantage of the mobility of the infantry, to allow guerilla type tactics? What was their logistic capability, and how did they handle getting supplies to the forward battalions in the artic conditions? What type of vehicles were used, or did they use dog sleds etc.
MTN in HOI3 were designed to cover a range of Div types, from the alpinists and artic specialists, to jungle specialists - with MTN having bonuses for fighting in jungle provinces. Different weather, but similar situation of operating in remote situations, low infra, using ambush tactics. Obviously it was stretching it a bit that JAP could have a MTN Div which could fight well in the plains of Siberia, the mountains of Yunnan or the jungles of Burma.
MTN surely would be ideal for FIN to give them the clear edge against the SOV INF in the Winter War. Did the starting OOBs just give FIN normal INF?
I'm not clear that MTN are "special forces" given they are Div strength, they are hardly commandos. And if their equipment is "light" (less heavy weapons) and reliant more on pack animals than trucks etc. they should not be very expensive in IC terms to build. This was probably done to stop majors spamming them.
Hopefully HOI4 might reflect this better with a split between the equipment built in factories and the training of the men. And given that every kid in some countries learns to ski and are used to the severe artic conditions, then perhaps the way to handle the situation is to make training of MTN difficult for all countries, except for Scandinavia, Switzerland, Nepal, Tibet etc. Then these countries get a clear advantage operating in their own territory against regular INF invading them.