Nobody who think expect that every weapon you carry should show up in a game where weapons is common loot.
It only work then you have maximum 3-4 weapons you can carry totally.
However nobody expected that holstering held weapon, a feature who has been standard since Morrowind is removed.
Armor is not the issue, neither is armor parts, they use an offset value for various parts, its the back and the left side who is relevant here. Yes weapon modding is more of an challenge, you could have some weird setups like an giant scope and a huge drum magazine on an small sub machine gun as an example.
Here the inner parts will clip inside your leg and might look stupid. On the back it would be far less visible. you back is static. Clipping into the back will not be very noticeable during play.
Not as noticeable as stuffing an fatman up you ass