Great!
*******
Finland campaigns – back to the paratroopers! 
1. Some history:
On October 1918, an American airborne assault (involving about 12’000 parachutists) against the German stronghold at Metz, in France, was about to be planned… but the armistice stopped it!
Anyway, shortly after the Great War, the officer in charge of the preparation of this plan, now a general, persisted in this line of thinking and six soldiers realized a successful demonstration in front of observers… Although the US observers dismissed the concept, not all of the observers arrived at the same conclusion.
And it’s
the USSR that was the first nation to take a serious interest in parachuting to introduce ground forces into battle!
Firstly, static line parachuting was introduced in USSR as a national sport and the population was encouraged to join the
Russian Airborne Corps. The German observers eagerly grasped the idea as well and planners worked quickly to develop an effective military parachute organization.
For the first time, in August 1930 at Veronezh (Russia), Soviet paratroopers participated in military maneuvers
, and their actions were so effective that a repeat performance was given in Moscow one month later. The Red Army created a test unit in 1931. By 1935, the Red Army was able to employ two battalions of parachute infantry in field exercises.
So, by 1935, the Russians were off to a head start on Airborne warfare and made the world's first spectacular use of parachutists!
Beginning in the mid-1930s, several other European nations followed suit. The prewar Soviet example
inspired enthusiasm among the Germans, French, and British. (
The British organized parachute forces in 1936 and used them continually in their maneuvers - so, as in Normandy . The French organized a parachute battalion in 1938 but inactivated it in 1939. The Germans launched a particularly aggressive program… By 1940 Hitler had 4,500 parachutists at his disposal, organized into six battalions. Another 12,000 men formed an air infantry division designed as an air-landed follow-up to a parachute assault. A force of 700 Ju-52 transport planes was available to carry these troops into combat and each Ju-52 could hold up to 15 men.)
Anyway, back to the Soviets: Despite its early entrance upon the Airborne stage, the USSR made little use of Airborne troops in World War II. But still, the Soviet Union made the first combat use of parachute forces. For example, on 2 December 1939, as part of its initial abortive invasion of Finland, the Red Army dropped several dozen paratroopers near Petsamo behind the opposing lines.
Alas for them, they apparently came down
on top of a Finnish unit
, which shot many of them before they reached the ground. Subsequent Soviet attempts during the Finnish campaign to employ airborne forces, all rather small in scale, met equally
disastrous fates. This
bad luck has the consequence that their later activities were principally concerned with the dropping of supplies and individuals for guerrilla activities…
2.
The actual scenarios…
Therefore, having seen this historical background, soviet paratroopers must indeed be added (
as already suggested). You have large-scale scenarios as well as small-scale ones, which is perfect because it offers many options to this regard.
To be as historically accurate as possible, I suggest adding some Soviet paratroopers (but not much), around the end of 1939 or the beginning of 1940… in a mission to “cut the Finnish supply lines”...
Then there can be an objective (
primary or secondary?) to destroy all these paratroopers units… and, as soon as this is achieved, an event with something as “
Despite the daring use of Soviet paratroopers, our brave soldiers managed to slaughter or capture them all! Probably the enemy will have learned his lesson and will never try it again...”
Perhaps even with as well an opportunity to intercept them in the air to weaken them already a little before their dropping?
So, it would be historically fine, it would reflect the initial real interest of the USSR for paratroopers… and it would make it clear why one wouldn’t see any more of them on the battlefield directly for the rest of the Finnish campaigns! 
It was a Soviet operation to have an excuse for an invasion. Wasn't the only one, either.
So, they could for example be added via an event when the time comes, appearing with a "Medical Jeep" core-unit named "Les Rochambelles", couldn't they ?