There are lots of things to keep in mind when doing high quality textures, especially for metal. You need to think about edge wear, rust accumulation (where would water pool?), dust accumulation, the environment where it spends most of its time, etc. Without a special automated software like dDO, you’re going to be doing a LOT of hand painting to get what you’re looking for. Specific things that come to mind are rust accumulating around rivets in the direction of gravity, damage and scratches along sharp edges, and overall wear and tear from pH differences in the environment with regards to intended material (i.e. a ferrous material is going to corrode and rust fairly easily while something zinc plated will get white oxidation buildup and gold will probably just get surface gunk buildup and scratches). It helps to have lots of reference images of the type of material you’re going for. Another thing I would do is have “USG Ishimura” either as separate geometry or paint, commit to one or the other, and use a different font in either case. Don’t just have it affect the normal map as it will look fake from glancing angles. You may want to completely remove it from the texture and instead have it be its own decal mapped to an empty so that you can move it around in a non-destructive manner. You should also give it some wear and tear as if the paint has been worn away. It’s pretty easy to accomplish with a couple of filters in PS or GIMP. Anyway, there are always a lot of things that can be done to improve texture quality. It’s just a matter of how much time you want to put into it and how close you’re going to be to the given details.