It's most likely a design decision to make the colors more vibrant and stand out. All the ships seem to have a lot more color vs just a stripe of paint here and there. My initial reaction was that the ship, especially the ones with an orange coat of paint, remind me of the Expanse. Blue making the ships resemble UN ships and the orange resembling the MCRN ships.
The KOL ship does look brand new shiny. But in my opinion, it makes sense. It doesn't look like the KOL we know; it looks like an upgraded version. The old KOL looks like a repurposed trade ship, this looks like they like the TEC said we need a stronger ship of war, use the existing KOL prefab and make it a ship of war. Just look at it, it looks brand spanking new with more armor reinforcements and bigger guns.
If you look at some of the other media images, it does look like some of the ships have worn paint and seasoned exteriors. Such as in this one: https://www.stardock.com/sinsofasolarempire/sinsofasolarempire2/media/screenshots/ann/sinsII_ann_ss02.png
Although I do think there's nothing wrong with the KOL looking ship to be "clean and shiny", I hope this treatment wasn't for all ships. Could be cool to have ships that start out looking closer to the original series and as you progres, perhaps you unlock the newer model of ships. Or maybe just have the fleet consist of new and old ships. It might just be too early in the development to see what the other ships look like.
I also like your idea of having veteran ships have battle scars. Would be a cool feature to see them implement.