I found a way to disable the use of the remote default gateway when using a VPN in Windows 10 build 10074 (Split Tunneling). This is indeed done with the PowerShell commands (thanks to a message from chrone81 on this forum).
You have to open PowerShell as an Administrator and input these two commands in the Command Line Interface :
Get-VpnConnection
Set-VpnConnection -Name "VPN Name" -SplitTunneling $True
OR
If you go to here: %appdata%\Microsoft\Network\Connections\Pbk\rasphone.pbk open with text editor and for every Vpn connection listed change IpPrioritizeRemote=1 – change this to 0 to disable