Unfortunately not all aircraft are capable of selecting a new departure procedure easily, I'm thinking if eg 737 which doesn't have a capable fmc for route 2 options at this time yet.
Regarding coding it in fmc through nav data provider, you are correct this is the chosen method of distribution.
Let's get this right, I'm not attacking anyone, but I think the capabilities vary and need to be taken into account.
The question wa about EO, that was and should be answered, nog about how it can or can't be achieved in a specific aircraft type or not.