by Nemesis420x
I'm really just relaying what others have said here;but conserving actions is valuable, and moving a large fleet is very costly in this respect.
The Eridani are a perfect example. There is a very good reason why their dreadnoughts have +1 embedded energy. They really don't have the influence to be able to move a large fleet, particularly early in the game, unless by luck they manage to draw best-case scenario planets that produce a whole lot of economy. Taking even 2 move actions to move the full force of their fleet would seriously hamper their ability to do much else with their early-game turns.
