Partisans are extremely cost efficient units since the do not pay a premium for m being able to infiltrate.
Partisans are everything but cost effective. They are sometimes worth their initial cost, but they are never worth their reinforcement cost. That is exactly becouse they pay no premium for infiltration. They should pay the premium, but their initial cost should be lower, so that they are cheaper to reinforce.
So why do I think they are not worth their 210 mp when not infiltrating? That is becouse they are the only 4 men close range squad in the game apart from pios who have much more utility. That basically means they cant be used effectively in combat becouse they die too quickly. They also dont have the OP granades or dps of commandos to be really useful in ambush. Nor they can plant demos. They also don't have the vet0 RAcc bonus, other combat 4 men squads get. In effect, the only thing they are really useful for after initiall callin is building mines behind the lines, which you can also do with more cost effective and universal squad of combat engineers.
If you have ever played or seen somebody play partisan commander then they get non-AT partisans very rarely or they sacrifice squads once they have too many of them, just becouse these squads couse way too much bleed in the long run. Merge sadly doesn't work in this case either as conscript models make the unit even weaker than before.
If I was to buff partisans I would change their base cost to 180 (which gives 22,5 reinforcement cost like for example mg42) and I would add either 30 or 60 of infiltration cost, depending on ballance tests and the need of standarisation. I would also think of giving them some small vet 0 RAcc bonus.
If I was to get fancy and add something unique to them, I would let them merge into other squads as well. They would be more expensive than cons, but could actually improve the squad they merge into. That would be also a cheaper way of sacrificing squads if you happen to get too many of them by infiltration.