Although, Set-AzureVNetConfig can create one or more virtual network(s) at a time according to the network configuration file, Remove-AzureVNetConfig cmdlet removes all the virtual networks under a specific subscription one shot. This is not logical because I might need to remove a specific virtual network not all of them. Therefore, I suggest adding -VNetName parameter to specify the name of the vNet the user wants to remove.
Cheers,
Sherif Talaat
PowerShell MVP