Continuing the discussion from He who controls the spice controls the universe:
Various locations of the Star Wars, Star Trek, Battlestar Galactica, Dune, and other SiFi Genre sagas each express certain factional loyalties.
In history, major armies have won battles for territory, but not always the underlying support of the populations in each region. The USA poured hundreds of millions into Germany and Japan after WWII, yet it still took over a decade before our soldiers and sailors became accepted in public there.
I think it would make NP2 more challenging to set up star loyalty /disloyalty impacts to production on stars after a battle.
The winner will need to garrison more heavily (marshal law) if the recently taken star is very loyal to another empire.
Whoever owns a star can boost loyalty with infrastructure purchases.
Over time (maybe 3-5 production cycles) with lots of loyalty boost spending on that particular star, the population shifts allegiance and the heavy garrisons will no longer be needed.
This also gives incentive for an empire who lost a star to retake it quickly. There is already a somewhat loyal population there that neither requires the garrisons or EIS spending compared to taking a star heavily loyal to someone else.
Some combination of
1 Star Loyalty factor to the owner
2 Garrison level
should result in a production multiplier that impacts ship and research point production.