Dwarves have stone form... Is this like the two headed ogres?

"Many of the hero classes will probably come from the Hero units in Warcraft III. The following lists some Warcraft III Heroes and other Units and their possible placement in World of Warcraft. It's also likely that we will see new Hero classes not listed here, especially since there could possibly be more than one Hero class option for each race/class combination."

They aren't saying you can become them... They are listing the probable classes and their counter parts in WC3...

Keep in mind this was also from 2003