In their January 2007 issue, Games for Windows has an interesting article in where Bill Roper, of Hellgate London developer Flagship Studios, says that:

After the first Warcraft and when we were talking about Warcraft II, there was an idea for about a week where we'd open another portal open and have the Orcs invade the modern-day world. We had this whole cut-scene we were talking about where it was going to be dragons and F-16s and firefights and stuff. And we were like, "Man, that's going to be weird. That's going to suck. That's not going to be Warcraft."

Good thing that idea didnt pan out. Now we've got a great warcraft franchise and an upcoming Hellgate London series.