If different shapes don't look too great/ it gets cluttered, would having the ability to set a colour for a ship-class or its status help with differentiation? Though then you might get a ton of colours all in one place and you might confuse what's a hostile/civilian/wrecked ship and what isn't. Maybe a toggle in the display options to toggle between viewing things normally and viewing coloured ship-types / coloured statuses? Or maybe something like three concentric circles where one represents their diplomacy stance (civilian, self, neutral, hostile, wrecks etc.), another for different status (probally one for if it has hangers and any docked fighters, one for if it has hangers and no fighters and one for if it has no hangers), and then another coloured circle for ship-class colours with non-player ships just having all three set to their 'diplomatic' colour to avoid spoiling/giving away information that shouldn't be known? Not sure what you'd do when you zoom out though- maybe merging them to just show their diplomatic stance? That sounds like it might get a bit complicated though.