Thanks a ton for these suggestions! I will add an inputfield next to the scale to make it easier to set everything to the same scale and will also add a inout field next to the "import" button which will automatically scale all imported objects to that scale, making it easier to import multiple files in a certain size ^^ I feel like that would be more intuitive or useful for people not experienced with blender rather than using blender properties (I can still look into it tho, I am just not very experienced with blender)
I am also working on expanding the textures that are supported, I want to add support for more texture/material properties ^^
For the serialization I used a unity asset, which let me easily choose to store the data as a json or binary if needed. The ability to look at the files as a json was a huge help for debugging and I do not know if it will be worth it to modify the code of that asset, mainly because I am not very experienced in this topic ^^' Currently it is not a big issue, so it is not very high on my priority list ^^'
Inbuilt version number is already intended for the next version ^^ (Idk why I didn't include that from the beginning tho)