Simple suggestion regarding Raiders.
Posted a while ago in another thread; copied here (slightly altered) by a heart overflowing with hopefulness.
(Please, all, use spoiler tags when replying/quoting with specifics about Raider behavior. The surprise of how spoilers behave is part of the fun of exploring the game.)
Raider fleets that will chase one of my fleets will always chase. (Some Raider fleets, like salvagers and troop transports, won't chase my fleets; that's fine.)
This makes it possible to kite them with a faster ship.
The chasers will keep up the chase for a long, long time.
I've never seen them break off a chase, and I've kited a single fleet for many months.
(They will break off if they take sufficient damage, but I'm talking here about chasing a fleet while not taking any fire.)
Even with early tech, small ships that are slightly faster than the Raider scouts can be built very cheaply and deployed to all systems.
Then, when a Raider scout arrives, it can be kited endlessly until a fleet can be brought in with sufficient firepower to destroy it.
This greatly diminishes the threat that Raiders fleets present, particularly in the early game--instead of needing a defense fleet in every system, you only need one such fleet that you can send wherever the Raiders pop up.
So, I'm proposing a very simple change to the Raider AI:
If an enemy fleet contains only ships that the Raider knows can match or exceed the Raider fleet's speed, don't pursue that fleet.
Instead, pursue other contacts (if any), or continue on the original mission.