1. Distance is still an important factor. Regardless of what people have said on the main forum, having trades spanning galaxies is still a valid tactic. While the long distance trade routes are not as profitable as before, a trade route from A00 to A29 is going to earn more for someone who trades only with himself than a trade route from A12 to A13 for a player who trades with 40 different people. Self trading a distance of 5600 lightyears (the maximum) is approximately equivalent to trading with 65 other people 1 galaxy away.

2. More trading partners is not necessarily a good thing. Due to round-off (we can't earn a fraction of a credit), the equation for income essentially becomes a step function and the length of the steps increases as the number of people you trade with increases. As you increase the number of trading partners, your income will increase, but not as dramatically as it will for the first half-dozen or so partners. Your optimal # of trade partners will depend on your patience in setting up new routes, and the degree of risk you are willing to accept in trusting routes to other players.

3. The number of trade partners becomes more significant the higher the economy. This is conjecture based on how I rounded off the calculation. Assuming all the square roots are calculated and multiplied before rounding, the higher the economy, the more likely the decreasing increase based on number of players is to cause the final number to round up.