The space around fleet circles provides an excellent opportunity to display information to the player. The mission "!" is a good start, but the following would improve the game's quality further:
- An eye-catching graphic for fleets that are trying to intercept the player. (A sound notification as recently suggested would also be nice.)
- A marker on hostile fleets.
- A marker on transponder-off fleets to emphasize them further.
- Indications that the player's transponder is off.
- A symbol for fleets that are detecting the player.
- A unique indicator for the player's fleet.
Planets/markets could also benefit from some additional graphics around them.
- An indicator for surveyed planets.
- A faction-color circle or an emblem or something on planets with a market.
- A marker for markets where only black market trade is possible.
- A marker for markets where no trade is possible.
- A special marker for player-owned markets.
All of this information is already available, these suggestions would only make it easier to see.
As a demonstration, even simple triangles could cover most of this information. Please excuse my crude mockups:
Spoiler
Player fleet:
Hostile Hegemony fleet:
Unknown fleet intercept:
Pirate market (with faction flag) refusing trade: