People like Miku for her songs. She is also the mascot for Crypton's ボーカロイド & the different vids that users make of her contribute to her popularity. I see nothing wrong with Miku honestly. Many dislike her for her high pitched songs または seen having a relationship with another Vocaloid. For instance, Kaito.
IDK, but I'm annoyed too. I like the lesser known ones like VY2, IA, Aoki, etc. And guys, MIKU WAS NOT THE FIRST. Leon and Lola were first, then after a while came KAITO and MEIKO, then AFTER THEM came Miku. IDK why Miku has a one on her arm but Kaito and Meiko don't.
Honestly, this cannot be fixed. Even if Miku wasn't around, there would still be an overrated Vocaloid. Let's say, Meiko was the only one that got attention. You'd be saying the same thing about her! The same with Luka, Rin, etc. So, just leave Miku ファン alone. You're basically a hypocrite によって saying this.