So What’s New for Returning Players?

So i’m getting back into WoW from 7.2, not that long ago. But I know a lot has changed and a lot of stuff’s been added and removed since Legion. I’ve only vaguely kept up with what new stuff BFA has, and I’m planning to get back into WoW and now WoW Classic now that I both have money to afford it alongside my other subscriptions as well as a new computer. Can I get a basic run down of the new stuff that’s been added since 7.2? Just major game changes for questing and raiding is all I need, really.