I've seen a few bloggers mention professions recently and while I await their posts to see what they have in mind for fixing professions I have a few ideas of my own that I would love to see them implement.
The Perfect Design:
The perfect design for professions can be based off Inscription. At least until Cataclysm that is. Taking away the fact that cataclysm has offered nothing to continue the feeling that made Inscription a great profession, it is still a very well designed profession.
Peacebloom was useful for inscription even at level 85. That is the key to what made inscription such a fantastically developed profession. Something you could make at the starting levels would still be needed at max level. This gives the profession an extended life. It also means that no materials become useless after you pass that time in the leveling process.
Take leatherworking (with skinning) for example. I am sure we have all seen level 85s going through low level areas killing things and never skinning them. Some do skin because they know that leather still sells well but most just figure that the leather is useless to them so why waste their time and bag space to skin anything whereas an herbalist (with inscription) will get just as much use out of stopping for peacebloom at level 85 as they did at level 8.
With most professions once you pass a certain skill level you will never need the materials from the previous skill levels. With inscription that is just not true.
Outside of inscription (again forgetting they screwed it all up this expansion) all other professions are completely expansion encompassed. Alchemy only needs Cataclysm herbs. Leatherworking only needs Cataclysm skins. Blacksmithing only needs Cataclysm ores. Jewelcrafting only need Cataclysm gems. Engineering only needs Cataclysm... well, everything. Tailoring only needs Cataclysm cloth. Enchanting only needs Cataclysm enchanting materials.
Adding Old to the New:
There are a few ways that they can easily make all materials useful while at max level. The simplest one is just the change the patterns to require some older materials as well.
Doing it with new supporting needs as well helps two professions at once. A new plate chest piece could now require the need for 2 bars of gold plated thorium enchanted elementium ore. To make one bar of gold plated thorium enchanted elemenium you would need 4 gold bars, 10 thorium bars, 2 vision dust and 10 elementium bars. This means mining has a new smelting pattern and blacksmith needs not just current bars giving two professions a direct connection to the past.
You could make all types of combinations of such items needed.
For a simpler version you could just say the item itself needs some lower level components as well. The new tailoring piece also happens to need 4 bolts of wool cloth, 1 bolt of mageweave cloth and 8 bolts of netherweave cloth in addition to needing some embersilk bolts, dreamcloth and embers.
You could give each profession the ability to transmute something for their profession or make alchemy be the transmute specialist all around allowing one transmute per profession per day. 1 stack of bolt of linen cloth and 1 stack of peacebloom transmutes into 1 stack of wool cloth. Something like that.
All professions could easily integrate older materials into new patterns. Stacks and stacks of void crystals you can not find a use for? Well, the new enchant for melee weapons needs 4 of them, so you better get farming or have a nice stash.
Motivator to Get Out:
They are always looking for reasons to get people back out in the world, this would be one. As it is now, the only reason anyone would go out in the real world to gather resources would be to gather the current ones in the current areas or to get stuff for power leveling the skills an alt. There is no practical every day use for older materials so there is no need to stock up on them ever as things currently are.
In the same concept of getting out. Dailies for all professions can do that. As your skill levels up, more dailies are opened up to you. You can keep them "expansion" based if you wish but there would be many dailies and you could choose which one to do each day.
For example, each profession will have a vanilla, BC, wrath and cataclysm based daily, you can choose which one to do based on where you wish to travel, if in the case of leveling, where you are leveling right now. You can only do one of these types of dailies for each profession you have per day and it would award a bag of useful goods which would be random goods used by your profession roughly in the range of the quest you just did. Doing the alchemy wrath one might get you a wrath time table flask or some herbs along with a profession token and a skill point.
There will also be a localized main city quest, along the lines of the fishing and cooking quests. Something simple that could be done around the city. This would award a token for your profession which can be used to buy materials, patterns, etc. Something like jewelcrafting has now and a way to either get a second token for the day or the only token for the day should you not wish to go out and do the other one.
To handle token hording so people do not buy everything the second a new patch or expansion comes out, all tokens will become "old tokens" that can be traded up at a rate of 5 per day only. Which in my opinion is what they should have done with the dalaran JC & cooking tokens to the new ones. It only makes more sense.
The End Concept:
I think the desired effect of making professions all encompassing instead of expansion specific would be fantastic. It would make professions more a part of the game as well by tying other things to them like getting out, doing dailies, and requiring more then just whatever is current.
What blizzard needs to do is to not be afraid to change things when it comes to something like that. They have to embrace that sometimes change is good and there is no law that says that the new leather boots can't use any heavy leather to make them. Why can't they? Because heavy leather is a lower level leather is not a good reason. Leather is leather is leather. It would just need some older leather with the new leathers to make it work and be expansion specific.
I also think that needing resources from all phases of the leveling process throughout the entire game ties the game into one larger world instead of just being so neatly confined into expansions. You need to buy each expansion to play the one after it anyway, so why should the one after it have no reference in crafting to the one before it?
They can't just turn everything into how inscription works because not everything can be used all throughout the game like glyphs can, but they can make all materials useful as they are with inscription all throughout the game.
I can't wait to see how others would like to see professions changed. I know there is more I would like to see changed about professions but no changes that I would like to see stand out half as much as expanding the need for lower level materials does.