A full on space war sim. Think foxhole or planetside, but with additional features, like strategic aspect (stellaris, with simpler resource management and way smaller map - 10-20 star systems would be plenty) for strategy players who take role of government and fleet strategists, tactical aspects for fleet commanders (something like battlefleet gothic armada would be close enough), individual ships controlled by players or ai, from carriers and battleships to individual fighters (star citizen, x4, elite dangerous). All that with system rewarding players for following orders, option to court martial those who notoriously ignore them, and star system capture mechanics. Another layer of boarding ships, stations and planetary assaults would be great too.