The thing is that these "The Game - The Resource Pack" projects rarely look good. WoW in particular has a very distinctive art style and it's one that's going to be difficult to pull off in Minecraft without an insane amount of CTM. Even then I imagine that a lot of things are going to fall short, such as armor, simply due to the hard-coded restrictions on the game geometry.
Plus... isn't WoW kinda dying? Last I heard it'd lost the majority of its players. It seems kinda late in the life cycle of both WoW and MC to start on a project this extensive.
Now... with that said if this is a thing that you personally want to try making then GO FOR IT! If you're passionate about the subject then you should absolutely use it to inspire your artwork. Nobody should be able to dissuade you if this is your passion project.
But if you're just making it because you think it'll be popular or because people might want yet another "The Game - The Resource Pack" pack... don't bother. There's probably already more than a few of these out there that have failed to grab attention.
I know it lost is popularity but its still alive and kicking, and I'm tempted to make one, but dont wanna waste days and days of time for a pack that wount get used at all. That my reason why I asked people to see if its interesting or not.
While I agree on the CTM part, I would go without CTM for starters. I mean you will never get that WOW look in MC, its basically imposible, but you can get the next best thing.
Ill consider it and wait for some more input before making a decision.