I have been thinking about a design change in the game for some time. In the current mechanism, players configure planets to exploit their resources to construct buildings and transports. While the transport side has not be implemented, it's largely a queue mechanism that says, make me a transport and the system calculates, "ah, that will take 3 days" ... 3 game days later there is a transport.
Transports can be used to move materials between complexes and into orbit. One change is that transports will be distance limited in addition to volume limited. This means a transport can travel a maximum of 500km/hr, which means that a 1700km distance with 640 units/hr means one transport, on average delivers 58 units/hr. For a player to deliver all 640 units, they'd need 11 transports instead of 4. Even on a planet with unlimited resources, the result is an increase in time. [Edit: This feature has been implemented; I realized I could send from the planet editor to the complex editor a list of all distances between every complex that has a transport out and this complex. Therefore, I would need to do anything special to get those distances. This took only a few hours to implement.]
The other change is that each planet supports one and only one space station. We'll provide a variety of stations, and a player will get one chance to pick the right one. Too small and it takes longer to build ships because of limited resources. Too large, and it takes forever to build.
The final change is a real time element. The simulated aggregation of the planet is fine, except that you run into complications as soon as you add free running ships. Therefore the final change is that once the player reaches the solar system, they go from a simulated environment to a real-time one. This means that a planet, which is represented by the space station works more like a train system with ships running to/from other stations. In a solar system with 200 stars and 3-9 planets per star, this creates a maximum of 1200 destinations. Although realistically, once a player has the basics figured out, it's a race against time rather than an exploration and resource collection process; therefore, I imagine that no more than 10-20 stars will be exploited to the point where the player builds complex infrastructures on planets in order to achieve their goals, therefore, the actual number of destinations will likely be less than 100.