2nd gen - cute concept overly used, followed by sexy
3rd gen - cute concept overly used, followed by girl crush
4th gen - girl crush concept overly used, followed by ???
The point is that this happens every generation yet some fans pretend like it's the first time it's happened. I wish the same criticism was held for boy groups who consistently repeat the same concepts. IMO, boy groups with similar concepts are far more oversaturated than girl groups.
Lastly, I love that people always claim this but never have any suggestions of concepts that haven't been done before.