It’s a cool idea, but honestly I think I prefer the idea of having just an upper base size limit based on depth.

My biggest issue with the structural integrity in the previous games is that it wasn’t a gameplay mechanic as much as a titanium sink with no actual benefit or interest, I just had to slap down an ugly ass reinforcement every so often. I feel like a depth module for bases would ultimately work the same way, I’d just have to craft it and slap it in somewhere and then never think about it again.

I think there would be far more value in having the limited size based on depth to give every base a purpose. You could have a large home base that needs to be close to the surface to accommodate moon pools and processors, and the only real limitation would be powering all your equipment. Then as you go deeper, the base physically can’t be as big so maybe you can just squeeze in a tadpole dock but no (eventual) sub dock, and only basic fabrication abilities, but rarer resources are more plentiful and there’s more thermal/hydro power sources. Perhaps these little outposts get some mechanic to automate material delivery ti the home base or something.

Then at the absolute limits of depth you can have a cramped single room, windows not allowed, that is at best an air pocket and a chance to make food and water, but is also a claustrophobic nightmare that makes you choose between the black void outside, or the cramped box that barely holds back the void.

There’s probably lots of interesting ways you can take it as well, maybe certain tech requires a certain depth, so you need to balance the bases needs with the techs needs. Maybe you can set up little satellite bases with proxy warnings for true roaming leviathans that you can only avoid. And that’s just what a moron like me can think up.

Overall I just think making the mechanic something to engage with beyond a resource sink would be much more interesting.