There are 4 major flaws with base building that have persisted since the original game.
You cannot build bases like the ones which are manually placed down by the devs, because you cannot clip the terrain even slightly.
Terrain hitboxes are too inaccurate/aggressive, obstructing your builds even when there is no contact.
Plants can obstruct builds.
Plants that do not obstruct builds, will clip through the walls and appear in the interiors.
With these problems fixed, base building would be much more enjoyable. Here are my suggested solutions
Allow base elements to clip into terrain slightly. A few meters at most. This would allow players to build bases that are partially embedded inside cliffs like the dev-built abandoned bases.
The above would also intrinsically fix issue number 2. I imagine making hitboxes more accurate would take much more resources, than doing this instead.
Allow us to chop down most plants with our multitool to make room for our bases. It doesn’t make sense for a tiny flower to obstruct base construction.
Use a render mask to stop hitboxless plants from clipping inside the base.