One of the things i really liked about Master of Orion 2 was all of the ship captains \ planet administrator characters they had. They were essentially "hero" characters and had a unique portrait and provided the ships \ planets \ whatever they were in charge of some nice bonuses. They didnt do anything overpowering, maybe +5% damage dealt, or a small speed increase etc. They made the ships \ systems they were in charge of seem more important and less generic.
I think this game would definitely benefit from this kind of thing. Especially if they include faction leader characters. They could each give some kind of small empire wide bonus ( like +5% trade income, or -5% damage taken etc ). Maybe even give them specials the same way that capital ships have them. Perhaps something like a pre-battle speech move where once activated all ships get a combat bonus for 5 minutes?
Character experience would be really great as well. Level them up to get new specials or increase their bonuses.
In MoO 2, it was a random event each turn whether or not a hero would approach your empire for a job. You had to either pay their hiring fee or decline their offer. If this game implements a reputation system you could even match up the heroes to the empires they are most suited for. That is, warlike heroes would try to join the aggressive factions etc.
As it is currently, I dont really feel anything towards the other factions.. i basically just see them as their faction color. "Oh look, the blue dudes are getting attacked by the yellow guys. Oh well, im too busy fighting the pink guys to help out."
Just imagine if those messages you received from other factions had a character portrait attached to them to make them seem more personal \ important. "Gad zooks! Princess Leia is being attacked by Darth Vader! I must save her!"
You get the idea