"We" doesn't necessarily mean "I" want to keep them, it's a nicer way of saying "you guys" want to keep such shields. I can have her shield power nerfed, and she would still be playable because of how much utility she would still have.
The shield values should have been the nerfed version since release, because of how much power it can do. No, it's not just a shield, it triples as a positioning tool to land more poke, an autoattack steroid that won't go away even if the shield is broken, and even doubles as a point-and-click damage spell slapped onto one ability. Basically, it does THREE additional things other than "just a shield".
Janna's shield has a higher base power because it only does ONE additional thing: give AD. The bonus AD goes away when the shield breaks.
Karma and Ivern, on the other hand, have the nerfed values as base shields. Karma's shield ability can potentially do TWO additional things: give off movement speed and can be potentially casted on more than one person. Ivern's shield also can potentially do TWO additional things as well: release a burst of damage and slow surrounding enemies. If that's the case, Lulu's shield base power have been nerfed since release if that is going to be the comparison.
It's not that someone who mains a said champ is allowed to say he/she is overpowered, right? It's totally not okay for some X champ main to say X is overpowered and should get nerfed!