I spent a good portion of time last year working with server extensions in arma 3. I wanted to create a simple way to interface the script and the extension and to make adding functions into the extension as simple as possible. I came up with Command Requests as a solution. I use the format "Command|Parameter1~Parameter2~Parameter3" to make requests in the extension. I simplified the RVExtension down to just 5 lines of code. I am taking this code from a project I am actively working on so some functions called are not described.
I created the CommandRequest and Command classes in order to simplify how the commands are handled. The CommandRequest class parses the string into its Command and Parameters. The Command class is a base class to every command that is added into the server extension (more on this down below)
The CommandRequest class is very simple.
The constructor splits the strings and formats the Parameters that are not blank into a string[]
The Command class gets only a tiny bit more complicated.
The static getCommand function returns the class that is represented by the command sent into the extension or it returns an empty command class.
Execute however is a virtual function. This is so we can override that function inside of classes like UpdatePlayers (more info below).
All that is left is to extend Command from our UpdatePlayers class and override the execute function.
Now, when "UpdatePlayers|Player1" is sent to the extension via CallExtension, the function execute(string[] parts) inside of the UpdatePlayers class is called with the parameter {"Player1"}
Most of my newer extensions inside arma run off of this method. I am by no means great at c# but I found this simple and easy to work with.
I used the info from Maca134's github to create the base project (more info on that here).