I think that the 'WASPI' case is also that the rules changed when it was too late for millions of women to do anything about it. This is also true of the various other groups who are fighting for restitution - WASPI is just one of them.
I feel that the state pension should be 'earned', in the sense that people would get a pension if they paid NI. I think that there should be no difference made between those who paid in a lot of NI and those who earned less and consequently paid in less - it should be the same payment for all, dependent only on the number (as opposed to the monetary value) of contributions made.
I also think that those who did not pay NI because they were ill, or unable to get work (millions in the 1970s and 80s) should get credited contributions, but not people who 'chose' not to work but could have. If people were willing to live on their partner's salary when they could have been paying in, they should live on their partner's pension - it's only fair.
However. Whatever the rights and wrongs as I see them, I think that it is grossly unfair to tell older people now that what they expected to happen, and the basis on which they made plans for retirement, no longer exist, and that they will now be significantly worse off than they were led to believe would be the case. If the system needs an overhaul, it should happen much more gradually, so that everyone has a chance to plan accordingly, and this should apply across the board.