First, get rid of all the pointless moving of "stone tablet" from one system to another.
The whole idea of moving contracts that are measured in TONS are utterly pointless.
Divide the Power play into something useful like:
Spy / intelligence gathering
Opinion maker influence a system to change alliance by shifting the fraction in control.
We can already do that today.
Assassination
Trade blockade, block ships to come or leave a planet with a ruling power.
Capture bases and outposts and keep them in control
Setup key mineral and metal extraction operations
make it more personal, give each player a "handler" who will give you missions to do, and by doing them you help the power to win the system.
if you are good you will get higher rank "handlers" who will give you more high end mission and more dangerous missions too.
there are a lot of things you can do to make it interresting.