The distinction seems kind of pointless aside from centrally setting wages - the Soviet Union could set 'prices' to whatever they wanted, but a finite amount of it was still in the system. Thus creating perpetual shortages when production wasn't adequately expanded, even if in theory everyone should've afforded it.
Why?
Mandatory subsidies forces factories to produce at maximum capacity and employ at maximum capacity regardless of whether it could be more profitable to just produce less or employ those people elsewhere. Thus, chronic goods shortages and excesses compared to a market economy.
For the wage situation, being able to set the wages is the obvious solution - you can allocate as much money as you'd like for people to buy cars, but there are still only as many as are produced.
And most/all factory profits should also go straight back into the government budget to use for any other economic activity. I fail to see how this would not be good enough, the player would be in control of both demand and supply while having to deal with some inefficiencies due to the rigidity of the system.
The big problem with economic planning and any game, is that the Soviet Gosplan nor any other real person in the world would ever have perfectly accurate data to plan production and consumption for any given moment. But in Victoria 3 (and 2) the player is nearly omniscient and can fix it all - no erroneous reports, no needing to check if quotas are fulfilled, no black market possibly obscuring activity.
And frankly, it's doubtful if the game would even improve as a result of obscuring that information.
Within the Soviet planned economy, most companies did not trade with each other. The prices only applied to foreign countries and consumers.
Please do not now mention the partially still existing private sector.
Yes, the system had its problems and it hasn't stayed the same for over seventy years. It's more that it aimed to get away from the commodity character. However, this cannot be simulated within the game, since the individual companies still have to trade their goods on the market.
P.S: please don't bring in politics now. It's all about the logic the system was trying to use.
Edith:
In order to more or less simulate the Soviet planned economy, there must be the following things:
- Profitability as such gone.
- Access of the companies to the required raw materials for free. The state decides which companies get what and how much.
- Consumer access to goods either directly or through wages. Again, the state decides how much and at what price.
- Possibility to limit mobility.
- Possibility of forced labor.
- No unemployment, since indirect work pressure was mandatory.
What cannot be simulated, what otherwise does not work:
- differences in the quality of the goods
- Transport losses
-Planning error
- Information leaks/fraud/competing interests.
Practically for something like this, the in-game planning economy would be the best system. The player would have full access to everything without any disadvantages.