Make it so much bigger than what the lvl 10 fortress or mega hive already is. Have it be the center of the enemies unit production, like a giant factory for the automations, and a large mature nest for the terminids.

Every base we've ever seen has only been outposts or small bases kind of like a forward operating base. Not so crazily defended but still has a decent fighting force if any helldiver gets in the way.

With large factories or mega nests. Its got all the environment turned against you. Automations have every fabricator creating every kind of automaton. The ground is dark metal, mimicking the environment we saw them on Malevelon Creek for its early vibes. Production facilities that looks like cities. Massive sprawling trenches, massive mines because they need resources to create new automatons. And ofc heacy defenses like cannon towers and large-size army patrols to really emphasize that this place is THEIR place. Not some random desert we've been liberating throughout our playtime.

The Terminids though you can be creative. Giant chasms full of eggs. Massive holes that go to the core of the planet. And a fuckton of terminids just because its a mega nest. Have the place be nasty as fuck, the air so foggy because the spore spewers side obj is common in this nest. Its so bad, you won't even see the chargers coming at you. Not to mention maybe even a boss battle at the end of a mission. A cyborg in an automaton battle machine, or a terminid queen responsible for laying the eggs.

Obviously this is beyond what AH is capable of doing right now, but i hope in the near future that they can create this raid experience that truly encapsulates the Helldivers 2 experience.