It'd be nice to have cartography missions. In uncharted territories, finding new wormholes to, basically, empty spaced and visit every quadrant to discover planets, asteroid fields and the like.

Being able to claim property of some stuff and trade ownership to various factions etc.

Being able to find routes to new sectors to expand your faction's territory.

The universe is, theoretically, big. Let'sd make it so!

Indeed. This is one of the original statements the devs made about the current multi-system universe. There will be expansion, but I would guess it will come well after cap ships and further mining and manufacturing additions.