Not being able to buy single items from a stack on the marketward.

[Wulfies]

Maybe I'm naive, but how is it difficult to use?
The most annoying part is the "default prices" it places on items, which seem to bottom out at NPC sell prices. This is the main cause for concern.
Other than that, the market works how a market should work. You can buy 1 from one vendor at a set price, or you can buy 12 from another vendor at another price. The vendor supplies the goods the way they feel will sell, and the buyer buys in a fashion that works for them. If an item does not sell how they hoped, the seller will change how it sells.
So 12 eggs. That's how 'I' want to sell it. If it does't sell, then I'll probably repackage it as 2 packs of 6. That's if a buyer doesn't buy it, and resell the 6 or so they don't need themselves.

The real problem is that supply-side has millions and millions of units of stuff to sell (in an MMO supply-side will always be over-matched than demand side). By forcing a 40 slot limit and only allowing only stacks, suppliers are feeling the pinch of running out of space.

Please read my post regarding Buy-Side AH. That would help alleviate this problem, by allowing suppliers to sell to people directly. Yes, there are counters, but I have addressed them in my post.