Mods shmods. Makes me think about a DLC of additional traits and abilities for custom factions. 20 of each would be nice.

Then, just to keep with the Extremely-Demanding-of-Devs theme, another DLC to get the AI able to build a custom faction with coherent flavor text pulled from a box-o-blurbs that are tagged to associate with traits, abilities, personalities, and other blurbs.

Could be much stronger replayability boost than the map generator, but probably ludicrously time-consuming to code...

I took a quick look at the xmls. Its not moddable the way they hav done the Torian:-

 
  <RaceTrait>
    <InternalName>AmphibiousAbility</InternalName>
    <DisplayName>AmphibiousAbility_Name</DisplayName>
    <DisplayNameShort>AmphibiousAbility_ShortName</DisplayNameShort>
    <Description>AmphibiousAbility_Desc</Description>
    <IsAbility>1</IsAbility>
    <Mod>
      <EffectType>CanColonizeAquaticWorld</EffectType>
      <Target>
        <TargetType>Faction</TargetType>
      </Target>
      <BonusType>Flat</BonusType>
      <Value>1</Value>
    </Mod>
  </RaceTrait>

The only EffectType's that are associated with Planets are Aquatic (Torian), Dead (Mercenary Ship), Extreme (Adaptable Ability). At presant we do not have access to the StatType.xml to add in our own or edit existing effects. Same goes for ModifierEffectsType.xml. Can just see whats there in the schema.