The ministry responsible for spending billions of Euros on extending the network will soon reach a verdict. Currently, citizens and experts can still weigh in. They have access to large amount of usage data - but that is only for current and past usages, not for future scenarios. Also, not even all experts can actually compute what happens when certain cables are built or not built and how likely any given societal benefit of any given option is - the problem is vastly complex (that's why computer scientists should be called to help in network planning). This is just being realised in Germany on a larger scale (i.e. bigger newspapers).

In addition, the cost analysis sometimes leaves out important details. For instance, the cost benefit of a cheaper power plant is taken into consideration, but not the additional costs of the extra cable which would be needed to make it available to all of Germany. Germany does not even define if it wants to be exporting electricity in 20 years or not. Currently, the network plans would support that. It is unclear to me if that would be most profitable for the owners of coal power plants in the east (as an expert claims in the interview linked to below), or wind farm owners (who would export during peak times). It is also unclear to me how much of these exporting capabilities are considered mandatory by the EU (who plan an integrated european market). It is clear that network operators would like to extend their network, because it will generate money for them, which has to be paid for by the users (that is: all German citizens).

https://taz.de/Ausbau-des-Stromnetzes/!104690/
https://taz.de/Wissenschaftler-ueber-Netzausbau-/!104694/