"lactation doesn't define or make good parent"
No, but the ability to lactate is an indication that the parent in question is a woman.
A feminism that tells me that women are unimportant, that the things their bodies can do are a mere logistical inconvenience that mean they have to have a couple of months of medical-based leave but no more, is not any kind of feminism.
I am the last person to defend any kind of gender essentialism under most circumstances. I don't believe being a woman makes you better at caring for children, or worse at doing hard sums.
But I do believe that being a woman means that you are biologically female, that all things working as expected you have the physical capacity to get pregnant, to gestate a foetus, to give birth (failed on this myself the proper way, but still came closer than a man could), to breastfeed.
Those things don't define me as a person, but they are important things my woman's body can do, and I want them respected and treated as important, not argued away as inconvenient footnotes.
I would happily support a proposal for a year of maternity/paternity to be shared between parents (noting the interesting points raised about how you establish who should do the sharing) on a 3 months each, use it lose it, 6 months divided as suits, basis.
What I object to strenuously is the needless attempt to reclassify the leave women take after their baby is born as special birth-recovery leave, to take a currently generous provision and make it short and potentially punitive (forcing women to the doctor for certs to prove they are still "unwell" if their recovery takes "too long").
There is no need to do that, except to make an ideological (and false) point that motherhood is just pushing a baby out your vagina, and once that job is done and you've been patched up you can fuck off if you think you deserve anything other than derision for the role you played in creating that baby and continuing to feed it.
This thread claims to be about equal parenting, but it is not. Unless you believe a working parent can't be the equal of a SAHP, the OP's proposals make no sense.
Equality in parenting comes from respect and consideration and love. It's based on what happens at home.
This throwback to the 70s suggestion seems to believe that it comes from whether and how much you work.