Some things I'm planning on adding to Polynaut, in no particular order. I'm planning on giving old school Elite/Frontier vibes, with some things different and innovative.

• Pirates
• More planet climates types
  • Carbon planets, with diamonds, crystals, and maybe some smugglers/higher chance of pirate spawns to fight
  • Frozen planets
  • Ecumenopolis/City planets, with stations to sell goods and trade, maybe some seedy underbellies to deposit black market goods
  • Gas Giants with more diverse moons
  • Tropical planets with fruits, maybe tropical diseases? (if survival mode is implemented) and lush biodiversity
• Warring Factions and Guilds
  • The Democratic Union of Sentient Species
  • The Human Empire
  • Manufacturing Guild
  • Merchant Guild
  • Mercenary Guild
• More ships
  • Small ships/fighters and bombers
  • Large ships/frigates, freighters, and carriers
  • Stations
• RPG-esque Economy
  • Trading, Freighting & Commerce
  • Black Market similar to the Elite series
• Non-Sentient alien wildlife
  • Passive
  • Hostile
  • Neutral (hostile if provoked)
  • Tamable
• Survival Mode
  • Health
  • Hunger
  • Thirst
  • Energy (need to sleep)
  • Immune System
  • Oxygen
  • Radiation
  • Body Temperature
  • Bladder
  • Fuel
  • Crafting
• Career Mode
  • Only survival vitals stats are Health and Fuel. No hunger, thirst etc.
  • Currencies valid in different jurisdictions
    • Union Credits
    • Imperial Dollars
    • Bartering/Trading in neutral or uncharted worlds
  • Purchasing instead of crafting
  • Landownership
  • Political Participation
  • Wanted level for crimes and/or $$$ debt owed (will trigger bounty hunters to pursue you)
    • Start your own crime syndicate?
    • Become a bounty hunter yourself
• Combat and Ship Maintenance
  • Parts break, need repairing from a mechanic or a self-repair job
  • Pirates, bounty hunters, naval forces will ambush you for a dogfight
• NPCs
  • Will occasionally see freighters taking off, NPCs both sentient and non-sentient wildlife throughout the universe with different tasks going about their day.
  • Dialog System: strike up conversations at bars, get in fistfights, buy things from vendors, ask around for information etc.

This is all I can think of for now! Large scope project, dunno how much of this will get done if ever. Feel free to chime in with your own suggestions!