For me it comes down to charisma.
I’m not, and never have been, a huge AC/DC fan. I grew up with their music but I was interested in more “creative” music. I have, however, dipped in and out over the years.
Bon Scott had a stage presence which was ol’ skool Rawk front man. He didn’t hide behind a cap, he had a great vocal range and had the crowd eating out of his well stocked jeans.
I find Johnson’s vocal style annoying. It’s a monotone screech. Watching him live (Memorial Drive, Adelaide), he was trying too hard to be Bon without having a clue what Bon was.
Yes, they have been way more successful since he joined, but I simply doesn’t like his style.
Still, what do I know ? I know nothing about music.