tons of Wc3 Maps has also turned into stand-alone games on steam over the years, now with current rules somehow Blizz would have to police the thousands of custom games out there that could potentially spawn their own game? and somehow enforce them as their own property ?impossible.
pretty much all the hundreds of TD games out there were once upon a time custom games on Wc3, if im not wrong Tower Defense games also first started off as custom games in Wc3