The most important thing is to have walkways around the entirety of the base so you can fire outwards as infantry and hop down as infantry, meaning walls aren't just an obstruction for all inside and only a minor obstacle for enemy Light Assaults, but a part of the base defense that ties the entirety of the outer defenses together.
Preferably other buildings are connected by bridges / roofing or underground (with the Control Console (CC) underground as well).
Courtyard (CY) domination is currently the most decisive way to win such fights and as you can see most these bases have some sort of huge easy way to dominate the CY from elsewhere than the spawns. Even from outside of the base (!).