For some weird reason Warlock used to be underrepresented in vanilla WoW. However, the least popular doesn’t mean that they were bad. Warlocks had amazing damage and some truly unique utility abilities allowing them to summon players or create Healthstones for the whole group. Similarly to Hunters, Warlocks were amazing for solo players with the ability to summon various demons to help them.
Note: My goal here was to create a comprehensive list of everything you'd need in order to learn to play any class (from Level 1 to Naxxramas)—meaning I am only including class-specific resources here (so no profession guides, general leveling guides, etc). Teeb's Resource list is much broader in scope, and I highly recommend you take advantage of it (as it contains a plethora of non-class specific resources as well). If you're not aware, Teeb is also responsible for the Race & Class Comparison Tool, Dungeon Tier Sets Gallery, and a huge variety of other insanely useful resources.
One may think that the AH may suffer a reduction of competitivity, leading to higher prices, but in an healthy server the gold farmer's farm will be taken over by actual players. Giving the chance to a more fair gameplay where you can go out and farm the materials that you need, instead to see them always farmed by gold sellers that sell them to you, without letting you many room to make gold in a fair way.
So even though you can play a WoW Classic demo today, we’re not done quite yet. We have lots of capital city features to look at, such as banks and auction houses. We need to test our dungeons and raids to make sure the bosses’ abilities all still work correctly. We need to examine all of our PvP systems. But we’re committed to taking a close look at all of these and more as continue bring the classic game back to life.
You're absolutely right! I've changed the opening—I hope it gives you and your list the credit you deserve. As for those other tools, I didn't include them originally because I didn't consider them to be class specific. I'll include the Base Stats Calculator here, plus add a message at the top directing people to your list if they want a more comprehensive index!