Sorry I've VMs off atm so you can't respond to this message, but:
After you've got the terrain somewhat ready you could note me about it.
Some things to note: You'll need a pack called "jassnewgenpack" or NewGen WE with compiler addon called "JassHelper" in order to use the systems I make.
So yeah, I can make like 3rd person camera, for many players. But keep in mind there's a ~100ms delay in the arrow input. So it'll need to be mouse-controlled 3rd person camera.
Quests will be pretty easy to make. System for item storage too. About abilities, you'll need to clarify what kind of ability system. And for talents, sounds really easy.
Oh and they'd be much faster to implement to your map if you learned jass a little. Jass means just another script syntax, it's a coding syntax for warcraft 3. Gui is a graphical solution for writing jass, gui is graphical, for example the trigger "Melee Initialization" is in GUI format. But when clicking the top-most item in the list of triggers (your map's name with your map's folder icon), it'll open code box. That is the jass environment.
To learn more about jass:
http://www.hiveworkshop.com/forums/jass-ai-scripts-tutorials-280/converting-gui-into-efficient-jass-233227/
http://www.hiveworkshop.com/forums/tutorial-submission-283/simple-jass-tutorial-beginners-251698/#title
There's a lot of tutorials for anything about the world editor, and if there's something not covered, you can easily find help by posting the problem here:
http://www.hiveworkshop.com/forums/world-editor-help-zone-98/
Good luck with the WoW project, hope you don't abandon it like I do for most of my projects~~