Is WOW Classic too niche?

I started playing Wow during Warlords of Draenor and I'm interested in trying out Classic. I really liked when Timewalking Black Temple and Timewalking Ulduar came out, getting the chance to see those old raids as if they were 'current' content, so I think I'd be excited to see all the vanilla raids as if they were current like Onyxia's Lair, Blackwing Lair, AQ, Naxxramas, etc. I heard that the opening of AQ was quite exciting, something I wouldn't mind checking out.