BTW I've the hull_mod.csv file corresponding to the mod which is the reason of the crash. It specifies a directory in utils folder where the script for this mod should be, however the file in question is missing. Do you know perhaps what I need to edit in order to remove the call to it? I've tried removing the line regarding that mod from the CSV file but it only gives me crash on start (doh!).
You could set it to use a dummy hullmod script that does nothing, or if you don't know how to do one, use the same script as an existing hullmod.
Is there a way that factions should defend their colonies more aggressively, like if you invade a colony, the faction that formerly owned the colony may send a investigation fleet then a invasion fleet soon after?
There's already a mechanic where, following a number of hostile actions by the player, enemies of your faction will attempt to invade one of your colonies (not necessarily the one that was recently captured). This is in addition to the vengeance fleets that chase the player.
Though I suspect that doing a response for every single colony captured by the player might make the overall experience too whack-a-mole.
The special task groups may also show up in response to a hostile player being seen a faction's star system. The main issue with this right now is they usually won't get there in time to stop player invasions, since those work instantly; that's a problem to be fixed some time down the road.