Heros - A Hero acts a mobile set of modifeirs can that effect varius other things the player owns, they do this in one of 2 ways by holding a "Position" aka Planetary Vicroy, Fleet Admiral, Imperial Despot ect ect. Or by Performing a "Mission" aka Putdown Revolt, Espionage, Sabotage ect ect. Missions are temporary, Positions are held untill the player move the hero out of that Position. Each Position can only be held by 1 Hero but any number of Heros can share the Same Mission target. The player gains Heros by some means which they have limited control over. They could be Recruited from a Pool of possible aplicants or given to the player randomly as the game progresses. Heros could possible Die be wounded or captured by enemy empires (and tortured for secrets

Portraint - A small Picture of the Hero that serves as a visual identifier, could use a transparent back ground to alow your Empires Flag/Emblem to be displayed as the Back Ground (also saves artist from having to make Backgrounds).
Name - The name should be assosiated with the Picture to keep further enhance the recognition. The player might also be able to change the name at the time the Hero is recived.
Basic Stats - Likly 4-6 core stats that define what the Hero is good at. This will require a lot of work as every action needs to be based of these stats in some way. I will need to know all the possible things a Hero can do inorder to come up with a good list of Stats.
Skills - Like in HMM and KOH the Hero can have a limited number of Skills that do a wide variety of things and effect almost every part of the game. Each Skill comes in 3 strengths Begginer, Advanced and Expert. The player has limited control over what skills the Hero has. All Heros start with 1 or 2 skills and gain new ones as they get better. The player might only be able to select from a limited set of random choices or might select a catagory with the player randomly reciving a skill from that catagory. If their are any means given to the player to control Skills directly their should be some cost assosiated with this. For example if you can build a "starfleet accadamy" to give a Hero a skill of your choice their is a "tuition fee" and the Hero is temporarily of no use to you when studying.
Type - It might be desirable to put each Hero in a tightly defined type which would limit what kinds of Positon and Missions they can perform. Say for example only " Rear Admirals" can comand Fleets and only "Diplomates" can conduct Diplomacy. Knights of Honor dose this as it has a wider variety of options for Hero actions then did Heros of Might and Magic in which the only purpose of Heros is to comand armies. ON the other hand StarWars Galaxies dosent force any types on its Heros and the realy powerfull ones like Darth Vader were capable of doing almost ANY action with high chance of success. All succuss or failure is based on the Core Stats in SWG without any Skills. A third option might be to make a skill for each type we might want to have so if the Hero has the "Admiralty" skill they can comand a fleet and if they have the "Diplomat" skill they can negotiate for you.
Level - When Heros do well they can level up and earn an extra skill and or incresse the level of a skill. Their Core stats see some improvment based on random rolls that take into account some Race preferences like that in HMM and type if we include that.
Age - I think it would be interesting if Heros eventualy die/retire. This would be done by rolling an gausian off of a standard age. The server keeps this age secret untill the characters "number is up" and then it kills the Hero. The standard age would be in game turns and could be differnt for each race. So many races in Sci-Fi are described as having a life span of 6000 years soit seems kind of silly to have their characters crock in the same amount of time. For Balance the Heros with shorter life spans gain experience faster.
Sub-Heros
Sub-Heros exist to fill the nitch between full blown Heros and "stuff" that you build through normal industry. Each race would have access to standardized list of Sub-Heros that do most of the standard things Heros can do such as Spy, comand Fleets, govern planets ect ect. They have some of the qualities of Heros but can be made by the player in unlimited numbers. Sub-Heros would almost certanly fall into tightly defined types which limit what they can do, likly each can perform only a single speficifc Mission or hold a single type of position. Sub-Heros lack most of the destingqushing properties of Heros. Their Charactersistics are.
Core Stats - The same core stats that Heros have (or perhps only the ones that are relavent to their job). These are almost always lower then a Heros. Their might be the potential for these numbers to incresse with experience or tecnologes.
Type - As I stated Sub-Heros are focused on a single job, each race probly has 5-6 types of Sub-Hero and they varry from race to race.in what they can do and in the value of their Core stats. For example the Darlok "Spy" Sub-Heros have higher (hypotetical Core Stat) "Evasion" then the Spys of other races.
Level - SubHeros could also have levels much like though of Heros but I would advise giving them a level cap of say 3 or something like that. If a Level 3 Sub-Hero is earning a promotion then it could be converted to a new Hero at level I. Sub-Heros recive only Stat incresses when they level up and the incresse should be simple and predictable like +1 to all stats.
Picture - Just like the Hero Picture but all Sub-Heros look identical and have a "generic" looking Picture with costumes apropriate to their jobs.