Content you don’t like doing isn’t going to keep someone around though, that’s what’s going to be hard with Classic.
Back in the day raiding was enough, but that was because we were new (i mean, by the point of AQ we were 1 night clearing MC with pugs, so it wasn’t always bad) so it took a long time to do it. But now that nothing is new, that everything will be wrecked quickly, if people don’t want to do the other stuff, not going to be a lot to keep them around.
Not that that will affect people like you who don’t mind the solo stuff, it’s just a point of interest to the raider type.
Sad part is, a lot of people are going to be looking to raid on classic and there’s just not going to be enough raiding teams, specially if you pick the “wrong” server.