This is what I don't get, imo I think it is better to show materials before than after. At least if you show the materials needed before a maintenance the market has a chance to recover by the time the patch hits. Sure people will buy out items right away, and when it's done after a patch the price of said items becomes even greater because people don't have extra resources of said items.

When the information is known beforehand though, yes people will still buy out, but the competition can be a bit more fair because the advantage is no longer given to the person who can log on first after patch but rather who can continue to supply the market with the new demand.