I suggest to take the last 10 PW battles ( only games within the last 24 hours ), and multiply IP income through battles with 1 / ( 1+ victoryPercentage *2 )
Losers get between 20% and 7% IPs
Winners get between 100% and 33% IPs
In a total imbalanced battle ( eg. goode ( 2200elo ) vs [3do]stromgrid ( 1200elo ) ), winners get 33% and losers 20%.
That's fair.
Nobody can get the whole galaxy with playing against noobs.
Additionally I would add a property "battles" for each object
The value contains the number of played (battles * players for this battle) AT THIS MAP ( whole session ).
if 6 players fight one battle, the battle count 6 times
sector.importance = ( sector.battles /galaxy.battles *countSectors ) *( galaxy.importance | 1 )
planet.importance = ( planet.battles /sector.battles *countPlanets ) *sector.importance
Values multiplied with planet.importance:
credits/IP ( trade with locals )
IPs from battles ( multiply with 1/planet.importance )
Income by taxes ( replace mining )
...
This would provide you more Credits/IPs for planets witch are in the favour of more other players.