Okay, so this idea will add a new dynamic to the game that I think will foster interaction and planning between fams and improve strategy component of the game:

trade routes

What I propose is when a player from allied fams have a share, they get a 5% income and resource bonus from the planets in that system.

If the allied players' planets each have at least one portal in that system, the income and res bonus from all the planets in that system are increased by 50% for both players.

The effect of this will be to foster securing territory and shares between allies, and to provide an incentive for fams to maintain round-long alliances. 

Also, in wars, a prime objective becomes disrupting trade routes of enemies.

Also, in wars where an aggressor fam ends up with many shares in an enemy's systems, essentially 'winning' the war, the aggressor has the option to extract spoils from the systems in which he or she has shares, whereby after signing nap, the player of the winning fam gets the 50% income and res bonus that would normally be allotted the 'ally'.