i’d love to see an affix system like this for clothing, so that you can customise items more via tailoring. right now we can make items “fit” which is great, but i’d love to be able to add extra rags to them to make them ‘warm’ or sew some extra pockets in to add a bit of volume, or maybe some wood/leather/metal to add some armour value. this effect could be a % that goes up as your skill in tailoring increases, so that when you first start altering maybe you can only up the warmth of your hoodie by a few points for example, but as you get more skilled you figure out more ingenious ways to alter your items and the bonuses increase - and of course alterations could also effect the weight/encumbrance/volume of items in a negative way as well.
as for weapons, maybe a whet stone item so you can add the “sharpened” tag to bladed weapons, or a gun cleaning kit to keep your weapon in a good state.
…and nails. be able to weld nails on to anything. spiked sledge hammer anyone?