A long time ago, in an FL mod called 4.85, there was a group of friends who thought some large battles could be fun. They accquired some OC ships and began raiding Gamma on a regular basis. Pretty soon, more and more players began to notice that something was going on. More and more people joined in those battles. On both sides. There was usually more than one raid each day, and soon enough the sairs felt it was time to raid Alpha.
Back then there were several factions who offered bounties on sairs, and that meant that the mercs also took part. The OC bounty board had a very large sum of money that they offered. Later on, that original group of friends started the 51st (Rheinland military), and began raiding in Liberty. Soon enough other people joined there too. When 4.86 came, and the Hessians got their wonderful Jormungand, we pitched in there too.
The point I'm trying to make here is that things won't happen by themselves. All of you probably know some people who share your view on what would be fun. You should gather and do whatever it is that you think needs doing. If you feel that there are too few battles between sairs and OC... See above!
I guarantee that no faction with at least some dignity will just sit by and watch while you raid their homeworld. They will soon organize themselves and join the battle.
And to the devs i'd like to say: Easy access between factions that are at war is a must. The changes made in 4.86 regarding OC's and sairs was insane, imo. Moving a Ranseur from Alpha to Gamma was enough to take away every ounce of joy that you might have felt before.