A few different ideas that have been floating into my head at work.
1. Split the research bonus races get into 3, so that each tree can be set individually. (ie: A race could be expert explorers (Energy tree) but be rubbish with weapons)
2. Add "DisallowedColonyPopulationPolicy". Some races may refuse to exterminate, or refuse to assimilate others.
3. Revise the ColonyPopulationPolicyGrowthFactorExterminate idea to be more like ResourceEffect -- modders could decide whether a given ColonyPop policy has an affect on a race. Ideas: Parasitic or carnivorous (+growth rate%) race that for whom "Enslaved" means "Livestock" but not to the point of exhausting a population. Or, gladiatoral arenas (Exterminate or Enslave) where troops can hone their skills.
4. Increase the maximum number of races allowed in the game to 80-100, or add a screen for players to select which 50 of the X races they have in their /RACES folder that they would like to include in game.
We need to have more control over our spies. Add policy options to set:
* The minimum %Chance of success before the AI is allowed to send a spy on a mission
* Re-use the list of empire research priorities to let the player set empire espionage priorities. The combination of the above minimum success chance (85%) with, say, "Hyperdives" and the existing allow/disallow options for automation would let us say "You are allowed to steal research from empires we dislike on hyperdrives if you can get an 85+% chance of success"
* The minimum number of agents kept on counter-espionage (maybe)
Add a relatively low-risk to assess the level and strength of counter-espionage in a target empire. Have the result stay for a length of time similar to Operation Map.
Rework the right message panel to include tabbed filters with counts of the number of unread messages.
Add a "CanBeChanged" field to governments. This could be used to make "Way of Darkness" or other governments (Capricious Extra-Dimensional Intelligence, perhaps) be a one-way adoption trip."
Modify the AI to build more research bases and reduce the value/lab.
Add a new "Repair Dock" component which is a construction yard that exclusively performs repairs. This gives the player (and AI) a simpler avenue for managing construction bottlenecks and create repair-only stations near battlefronts.
Alternatively, add some kind of a for which construction yards can build new ships, or a percentage of docks reserved for repair-only.
Add 4 more columns to the tech tree, bringing the total to 12, and make the constant used for determining the cost of research in any given column moddable.
This could make life easier for those attempting major revisions of the tech tree.
Add "% ruins controlled" to victory conditions.
Revise the attack strategies to make more effective use of weapons. Right now "All Weapons" (from Icemania's testing) has the ship try to maintain 80% of max distance of its main weapon, which results in very poor damage for most weapons.
There are several ways to modify this, including:
* Making "All Weapons" try to maintain a distance where its main weapon does 80% of its max damage instead of at 80% of its max range. It may be easiest to add another field to the weapons to hold that range target rather than calculating it on the fly.
* Allow more refined control of combat tactics by specifying (%damage) of (shortest-/longest-ranged weapon)