Idk, I personally really like that Ayu's been performing WARNING so often. It's nice to see one of her newer songs become a concert staple instead of songs that are only 15+ years old. Plus, WARNING is super fun and energetic - it's really incredible to see it live.
As for independent and +, for some reason I just can't get into them
+ IS really great as a concert/encore song though. I wish she would've performed it more because it sounds like it was recorded to be sung live in concert