We do have such a server in our consideration. Currently we are adding one more machine to our network and when this process finishes, we will be able to add more servers. When oil rigs pop in a cv game is a reference to server 8 I guess. Such a server was very popular. This is the only reason for keeping it. Players like easy games.
As for making a server with only road,water,airplanes, it would be possible, but there are certain aspects to consider:
1: If you allow airplanes, trucks become useless....most of the players only use them to supply cargo to the airports because the profit is much bigger with airplanes
2: Ships overload the server, demanding a lot more CPU then it normally does. This is why almost all our servers have the ships max number set to 0
If you take those 2 arguments into consideration, the result is obvious: Have 1 road server and have 1 airplane server.
This is exactly what we`re thinking right now