Today Nethaera put together a list of upcoming Profession Changes(though warns these are not all of the changes - just a taste) and posted them on the official forums.
- Elixirs now stack in two categories, Battle (Offensive) and Guardian (Defensive) Elixirs. You can only have one of each type of Elixir up at a time. As a result Elixirs now stack with class abilities such as "Arcane Intellect."
- Four new defensive elixirs have been added. Two are on trainers, one is in Halaa and one is in Cenarion Expedition.
- "Flask of Petrification" can no longer be turned off during its duration, but it now will clear all threat from all monsters for the duration of the effect. Though monsters may reaquire you after the effect ends.
- The cost to purchase Imbued Vials has been reduced.
- Enchant Bracer-Spellpower had its primal costs reduced slightly.
- Enchanting recipes that increase spell damage now also increase healing as well.
- The "Major Defense Bracer" enchantment has been moved from Ethereum Researchers to Ethereum Nullifiers.
- A recipe for "Frost Grenades" and the "Icy Blasting Primers" needed to make them are now on engineering trainers.
- Engineering recipes can now be placed in engineering bags, as can engineer made fireworks.
- Many engineering recipes will now give skillups for longer than the previously did.
- "Seaforium" now opens locked chests as well as locked doors
- The Poultryizer and Nigh Invulnerability Belt now cause mishaps less often.
- The Goblin Rocket Launcher cooldown has been reduced significantly.
- 11 new epic goggles have been introduced at 350 engineering skill and are available from the trainer. They range from cloth to plate, and have a variety of stats to appeal to most talent specs.
- The fishing timer has been reduced from 30 to 20 seconds and it now takes less time to fish.
- The fishing timer can no longer run through its duration without a fish biting.
- Fishing has been removed from Arathi Basin and Alterac Valley.
- You can now fish in Underbog.
- The jewelcrafting UI now has gems split up by color so it is easier to find gems of a specific color to create.
- A number new gem cuts to existing gems have been added to the game. Included among them are a spell hit gem and more multi-stat gems that have attack power on them.
- Jewelcrafters can make two new melee oriented meta gems. One is found randomly as a world drop and the other sold by the <Faction> reputation vendor.
- Thorium requirements for most recipes has been reduced.
- Prospecting now always yields at least 1 gem. Overall, the amount of gems received from prospecting has been increased.
- New recipes have been added that use the Jaggal and Shadow Pearls.
- Skinning higher level creatures will give more leather; you will no longer get a single leather scrap.
- "Knothide Armor" kits now require less leather to make and give skill increases for longer.
- Leatherworking made primalstrike set now has an attack power set bonus rather than a strength set bonus.
You can check out all of the changes at the Profession Preview - 4/09/07 forum thread.