Problem is reducing block sizes becomes a time investment of exponential means. Lets say you make all blocks 1/2 their size. That means a person would then need to place 8x as many blocks to fill the same void as one. Yes, detail increases by 2x, but engine overhead and time investment increases by 8x. You could reduce block size by 25%, but the detail increase would only be 33% higher while increasing block count to 2.35 per the same section.
To make a smaller block set work without a massive change in player time investment and you would need a change to how the engine groups blocks and the toolset to group those blocks would need to be made. All of with would be a major change to the engine (much greater than reducing rendering size or increasing camera viewpoint).
Then the final part of what are you buying with this change? Remember size is based off perspective. Close up the detail would improve, but you mentioned stations which are typically large objects. Increasing detail by 2x would mean the blocks would leave view at half the distance you can see them currently. What is that view distance versus the games scale? I have an okay system, its not a graphic beast nor is it a potato with a monitor attached. At 500m the blocks start to lose their individuality, by 600 they start to be merged into each other. On a very high end system I could see that lasting to about 800m. The scale of starmade in a sector alone is 2km by default. So you could say in the default build at 1/4th of the sector distance you have the edge of detail.
Now if we switch that to 1/2 scale blocks that range would happen at half the distance, so at 250m you would start to lose detail. If the station is around 350m^3 then you essentially cannot see the entire stations details all at once. So you aren't gaining as much detail as you think. You gain up close, but you lose a lot at a distance. Which place do people spend more time in for the gameplay? At >500m or at <250m? I would give an educated guess that the distance they are at is about 400-800m usually which is currently the detail sweet spot with the current block size.
Now there are some graphical tricks to scaling block sizes. You don't have to make the blocks smaller, you can just double amount ofwhat you see. A wider camera view on the screen would do that. How to enforce that on all players would require a distributed mod.