User blog comment:Kogath/Monster Hunter X Discussion/@comment-12049719-20150914112742/@comment-5721990-20150914214434

Maybe another reason was that in 4th gen not only did they introduce 2 new weapons but all previous ones got an overhaul too (though some got more changes than others) so rather than introducing another weapon create the styles and arts. Possibly saving the weapon concept for the 5th Generation?