The English titles for both the 1993 and 2002 movies were created by Toho, not Sony.
While I think GODZILLA VS MECHAGODZILLA II is not a good title, it does a good job telling customers this is not the same movie as the 1974 film and that's the most important thing.
GODZILLA AGAINST MECHAGODZILLA is a direct translation of the Japanese title, so its funny that anyone is complaining about that. Here's a photo of Toho's publicity material showing the English title several months before Sony bought the film.
http://www.henshinonline.com/images/gxmg_intl01.jpg