That is correct. Any problems have to do more with commander and less with Partisan itself that are cost efficient. Unless one wants to redesigned the partisans.
Ehm, you got me wrong. Let's make a quick review of the commander to spot the issue (spoiler: it is AI partisans and low ability synergy)
1. AI partisans. On the paper, they are good infiltration unit, who can make a real impact. In reality, they have low performance and usually don't even meant to survive after infiltration. Additioanly, Soviets have another AI infiltration unit - AirGuards, who are doing much better and the only real disadvantage - no cloak, but it's not an issue.
2. AT Partisans. Good unit, has it's impact on the field. The issue - you can get it in doctrine with PPSh and ML-20, which has better synergy and more impact.
3. Radio interception. Good ability, but you have it in 3 other commanders with better synergy (iirc NKVD, Advanced Warfare and Armored Assault)
4. Spy Network. Probably it's good ability, if it comes with something else in the slot, or like passive for infantry with some radius. For example, Ostheer got ability like that (interrogation) with G43 upgrade. Additionally, it's potentionaly covered by Radio Interception, infiltration units and vet abilities from AT guns and TD destroyers.
5. Mark Target. Again, good ability, but you have it in several good commaders with something else, what works well with it (like Guards, T-34-85 or ISU-152).
As a result, we have commander, where you have some good abilities, which are not working well together, and Partisans, which are taking two slots and only one of them can be definetly called as usable one. For me the good way to go is merge partisans together into one unit, replace interception and do something with spy network.
Again, partisans are important part of the problem. Even if call them "cost efficient", it's no real reason to take this commander over other Soviet commanders with infiltration infantry units.
I am not sure how that would work since calling 2 separate them from ambient buildings would be difficult.
It would work better, because you will have one partisan squad, which infiltrate from the building and have some upgrades, like Taksin02 suggested.
P.S. It would be cool, if partisans can interrogate wounded soldiers and get weapon slot, which they have when were alive.