I agree with Revilla that directions to join the circuit "standard way" could be dangerously missleading. I would personally never follow such directions without prior verification with official VAC charts, especially after reading your warning, that actually "system has no knowledge about local conditions"

Then what is "standard" in the first place? As I know "standard" joining differes from country to country.
Moreover I can not imagine how practical would be selecting joining points: pushing fingers at poore resolution screen in possibly bad screen visibility conditions (sun) at one of the most critical moment of the flight, when you normally should look out for trafic in the circuit, listening to radio, identifying wind by windsock direction, etc...
This functionallity would be helpfull if one day real circuit geometry and joining/departing patterns could be shown on airfield plate.
All above critisizm is about joining the circuit. But I like the idea to give some information about circuit itself. I would give following:
-Frequency ( but not "Approach", it should be "TWR" or "A/A");
-Altitude of the circuit and Altitude of the runway (or Altitude of Circuit and its Heght above runway);
-Visual presentation of circuit (simplified, just to show on which side of runway it is);
-Clear runway numbers (you have it already on extended centerline, but I noticed if there are L and R runways, sometimes numbers overlap and difficult to read).
And all this better to be accesible during flight preparation, not just pop up during actual flight, as I still would be more comfortable if I can review and verify this data before the flight.