It seems much slower and harder to build up enough scraps to refine to get enough leather to make medium armor than it does ore or raw fabric. With ore and fabric nodes, you are guaranteed (assuming another player already used the node and left only the bait/style raw material behind) to get a minimum of 3 pieces. Sometimes it's 4. or on a lucky drop with the CP passive Plentiful Harvest, you can get 7 or 8. The same goes for Wood nodes.
Meanwhile, leather scraps can only be obtained by looting the bodies of specific types of beasts in the world and the loot drop rates for them are maybe 1 in 3 (I've gone as many as 8 kills before getting a drop of only 1 leather scrap. On top of that, there's a fair chance that leather scraps will not be part of the available loot and even when they are, you usually only get 1 or 2 pieces, or at most 4 on a lucky drop. When you need to gather 1000 or so pieces to refine to get the 940 pieces needed to make a full set of CP160 medium armor, the task only become much less enjoyable. True that you can buy from other players through guild stores, but those tend to be expensive, especially for players who have a harder time maintaining a BPM (Big Pile of Money) in gold.
Why make it so much harder to gather leather scraps than any other gear material? It seems a bit unfair to players who want to run medium armor over heavy or light armor as it takes much more work over a longer period of time (at let 3 times as long) to farm enough mats to make medium armor vs light or heavy. Perhaps 1 or 2 changes could be made to make for a more balanced armor-farming experience:
1. Increase the drop chance so that leather scraps could be looted more often.
2. Increase the amount dropped in each loot drop from beasts to equal the amounts gotten from plants, logs, and ore nodes. 3 per drop minimum would at least make the experience more balanced and faster, making it less of a chore to farm leather.