My own intent was to make starbase-anchored travel routes a central part of the game. Overall range would be the same as it is now (albeit slightly shorter), but outside of a very small radius from starbases or planets (5 pc radius, maximum) speed would be very low due to the lack of a large device to create massive warp bubbles. The effect would be more pronounced for fleets containing only small or tiny ships, and less so for fleets with large ships, but never outside a starbase trade region should ships be able to travel more than about 5 pc/month.
The idea with this is not just to introduce immersion and realism, but to add a strategic aspect of the game that is currently not present. Two civilizations, for their mutual benefit, may opt to build a series of jointly owned and controlled starbases between their local starbase-transport networks, allowing for improved trade and military cooperation. However, once the two civilizations have built up a dependence on the trade route, a third malicious civilization may declare war solely for the purpose of breaking the chain of starbases and slowing down travel, crippling the economy of the two participating players. Alternatively, a player may locate the fleets of another player it is at war with and note that they are near the edge of a hard range established by a starbase: knowing this, they may endeavor to strike at the starbase that is allowing the ships to travel as far as it is, causing the ships to wander in deep space until they either return to the player or (if evil) possibly join pirate bands in the galaxy.
I would also like to revamp the method of influence spread, particularly through the elimination of influence starbases and in light of multi-maps if they are implemented. Influence modules on starbases (and planets themselves, for that matter) should be unusable to claim territory, but should rather affect freighters that pass through the relevant starbase range and allow them to exert influence on the destination planets. This could of course be mixed with citizen races, cultures, and citizenships, which would make the game far more interesting and add other mechanics that will not be mentioned here. Deep space shouldn't be claimable, as it is impossible to maintain control over vast swathes of empty wastes, but planets should be.