Nice idea but I believe it should be on low priority. Also I think that this buy menu will not stand for long. For some reason it feels a little bit off to me. Maybe it's because it covers all your screen and there is not empty space for new guns or something. So maybe the next iteration of the buy menu will be so different your idea may not be usable at all.
We won't be adding new guns for a while, so the shop you see will be around for the foreseeable future (though we'll be adding some QoL stuff over time.) We like the current "all-up" layout because it presents all of your options up front, and makes mixing/matching guns, abilities, and armor a lot easier compared to other approaches.
In the meantime we'll look at ways to make broken armor more noticeable for folks who might be missing it.