I guess one of the reasons Godzilla vs. Biollante tends to be overrated nowadays is due to the fact that, despite its shortcomings, it's the best the Heisei series had to offer. Not saying much, but still. I've always loved this film, I loved the music (as jarring as it is), the characters, the story, and Biollante. I think that more and more people have started to appreciate it entirely due to the fact they want to like something
about the godawful heisei series...and they choose this.