So LW is an extremely challenging profession to make gold on the AH. If you want to make gold with LW, the best way is to fill orders in trade for gear.
LW gear (like BS weapons or tailoring gear) is popular in terms of the number of requests made. This causes problems for reagents which are used for these popular recipes. Because people crafting these will obtain reagents for free with resourcefulness procs, their cost for “making” the reagent is zero. This weighs down the prices below the cost of actually making the reagent.
Additionally, the multicraft wheel of the “Learned Leatherworker” specialization gives extra multicraft items. This additionally weighs down the prices below the cost of making the reagent, because when you multicraft, you can multicraft a LOT.
Together, these two factors have caused the reagents to go VERY far below the cost of making the reagent to the point where you MUST multicraft or you won’t make a profit. And you can’t even use mirror powder, the margin is too tight for that.
To make sure you multicraft, you will need to make items in bulk. The problem is there isn’t the demand to sustain many people making these in bulk. (which then makes people desperate to sell, which pushes down things even further.)
Not only that, we have gloomfathom hide and profaned tinderbox in a lot of our recipes. This means that making bulk quantities of these things is extremely risky. You could end up with a stock of items which cost you tens or even hundreds of thousands of gold that just don’t sell. And just one or two resourcefulness procs on those could make or break your profit margin.
So, if you don’t have “waste not” and “industrious innovations” completed, do not attempt to enter this market.
If you’re going to ignore all my warnings so far, then here’s the safest thing: Storm-Touched Weapon Wrap. Because almost all of the weapon recipes require it, it does sell fairly quickly. It can be made at a profit without multicraft if you buy R2 reagents and use concentration. It can be sold with below average procs of multicraft with R3 reagents, but again you MUST multicraft or you will not profit (for R3). In either case the profits are slim and any shifts in the market could make this go below profit level.
Second thing you could make: green profession tools. However, these items are REALM based (commodities like ore, herbs, are REGION based, but items that can be equipped are REALM based). You will have to check with your realm prices and do the math yourself.