I can't find the post now, but it was stated that the penalties are severe enough that empty space is more efficient.
Regardless of the purpose of a ship, removing 25% of its shield capacity makes it less capable. The only reason this is currently LESS of an issue (it is still an issue) against pirates is that the pirate AI is woefully insufficient to pose any real threat to players who have a clue what they are doing.
That is illogical. Regardless of a ship's purpose, more function is always better.
Be careful not to equivocate a yacht with an RP warship. I'm not asking for enough room to build a yacht with a zen garden and a party deck. I'm asking for room to stuff in a few bunks, a cramped mess hall, and the basics that real life warships have. Currently, adding a few bunks and a mess hall results in an objectively worse ship no matter how you do it. The best you can do is minimize the nerf to your systems.
The only reason to miniaturize systems is to make room for things other than systems. However, if nothing else changes, you will still see ships crammed with systems. The systems will just be more powerful.
According to the OP, only reactor chambers need conduits, and thus only reactor chambers would have efficiency problems. It seems unlikely that a ship of that size will need chambers, however. It is a very light ship.
Okay, more function is better. So why should the person who has built more function into his ship be inferior to the person who decided to build more pretty into their ship? As I stated earlier, when the full system plus the crew come in, then RP and PvP will become the same, essentially.
The reactor chambers will be less effective if they are built at the "corners" or far ends of a ship, that was hinted at in follow up posts by the devs. And seen partly in the images in the original post. And people have suggested that in order to defeat a "chandelier ship meta", making it so you have to run conduits here and there will make putting the power in the back and everything in the front less efficient.
As for adding bunks and messhalls, yeah, that's the whole point, the ship that fills everything is objectively better.
You can't fix that with a block system.
And by forcing people to build a certain way is defeating Schine's intended purpose of not forcing people to build a certain way.
I'm not arguing that changing how power works is a bad thing, just that the proposed system is not different from the current system, except some numbers are higher. Which could be done right now by any server admin or player, if they wanted to fiddle and figure out what number to change to get more power out of the power blocks. Schine could do it right now, easy peasy, and no one would have to gut their ships and redesign it.
Basically, you are losing more than you gain with the system. It's basically the same thing, but you have to change everything on your ship.
For a change this massive, there needs to be a purpose other than changing power for heat. A purpose other than forcing people to have some spaces in their ships. A purpose other than changing the power-cross-brick-ship meta for the "chandelier ship" method.