Warcraft 3 had much more single-player content for sure. Blizzard gave us this thing called Campaign Editor, which was a simple but effective way of linking multiple maps into a proper campaign. I probably had (still have) about 20 of those things, fan-made campaigns, and I would totally geek out and play through all of them plus the Blizzard campaigns in chronological order. Good times.
Of course, that's when Blizzard allowed us to have local content/local hosting and everyone's mission in life wasn't making the front page of The System. As for the complexity of the editor, I think the editor is great and has a ton of potential, but with the whole custom game system thing I also feel it's kind of going to waste.
So basically, the same old story you've read a million times during the past year and a half.