mighty igloo
The third academy slot should not be valued over say dock or dorm upgrades. There is no reason to go for that, especially given that if you keep them running your consumption of books can outpace your income, making even more useless.
Furthermore, the second floor upgrade in the dorm should be valued over the fourth dorm slot for active players - it lead to three more morale-boosted ships compared to the one given by a fourth slot,
That is to say an entire fleet, making grinding much less likely to be stopped by low morale, while also making the 20% exp gain from high morale accessible to all six ships, making grinding more rewarding even for less active players.