The key idea behind my suggestion is that there are 2 classes of items - those that are vanity items, and those that affect actual gameplay. Vanity items are those that have no effect on gameplay at all - dyes, ectos, shards, rubies and the rarer crafting materials. All these are wants rather than needs. On the other hand, we have items that change the way we play - basically the runes (of all types) and common crafting materials (since they're needed for armour crafting). What I would like to suggest is that the market for the two types of items to be separated.
At present, all of them run on the supply/demand/stock model from the traders, and as we have seen at present, for items with a high demand and low supply (such as ectos/sup runes), and with the price cap in place, stock of them is never/rarely available, and hoarders are reselling them for vastly inflated prices.
Instead, what ANet should do is to separate the two out. The gameplay items (runes and common crafting materials) should be a tightly regulated market that has unlimited stock, with selling prices from the merchants being monitored by ANet. The vanity items however, would be allowed a fully free market model - items prices not capped, stock being entirely dependent on people selling to them et al.
Why so? This would effectively create 2 markets - the gameplay market, in which players can always have access to the items when needed at reasonable prices, and not be subject to the whims of predatory hoarders, and that of a vanity item market whereby existing speculators/traders are free to dabble and play in. By separating the two, new and old players alike are free to obtain items that might complete their build without having to camp the rune trader at present, and yet at the same time, have an active market in which to dabble and items to work/farm for.
Having said all that, any suggestions/comments from anyone?