The blacksmith crafting mechanic isn't really a crafting mechanic at all, it's more like a replacement for the gambling mechanic from D2. Remember D2 had crafting as well, that system worked by combining ingredients you found in the field. You had a set number of guaranteed stats, and a number of random stats (up to 4 IIRC), with your level and the item's level determining the chance of getting the maximum number of bonuses.
This was great, because some crafted gear was good to have and especially good to make. Gambling on the other hand, was almost always a waste of gold. BUT, there's not really any point in having gold anyway so that's fine.
D3's AH seems to be following the whole 'gold is useless for everything except buying l33t gear'. Or you could use the gold instead to craft items. At least then you're making something out of your own resources, which I gotta feel is a better expenditure than just paying-to-win model the AH espouses.
One thing I'd like to see is potions and/or scrolls, and I think you can do so by introducing the third artisan follower they cut from the game. I kinda see it as a mechanic similar to the shrines in the game, only more controllable and last longer. And have different effects. So for example, let's say a potion of ironskin (increases your armour by X% for a minute). Upgrading the mystic can have various effects on the potions, from increasing the effect of the bonus to increasing the length it is active, or decreasing the cooldown between potion usage. There's a whole bunch of potion ideas you can add - the aforementioned ironskin, something that increases defence, speed or chance to dodge (maybe all three), something that increases resistances, maybe something increases your damage, and how about a heal-over-time potion? The only thing is, you'd have to overhaul the way potions work and maybe change the UI. But that shouldn't be too big of a deal. Hell, bare minimum they should do is fix the cooldowns for healing potions. I've died too many times because the healing potion was on a long cooldown and I was being chased down by monsters.