Cheap Thrills - I disagree with you that Joplin's vocals are "so imitated and so hackneyed that it feels like nothing special." It's hard to think of another singer, female or male, who really sounds like her except for the singer from Hop Along. But I think the problem with Joplin's vocals is that the heavy raspiness can get pretty tiring, even when it's used on good material (e.g. "Piece of My Heart", "Me and Bobbie McGee"), and when the underlying song is not very interesting (like most of Big Brother's songs from what I remember) then it ends up being all about the vocals.
That said, it's been a long time since I listened to Cheap Thrills, kind of want to take a relisten now. May do that this weekend.