One really important strand in a lot of feminist thought, particularly radical feminist thought, is decoupling the value of work from its financial rewards within a capitalist system. Caring work in particular is often very low paid (care workers in old people's homes) or not paid at all (SAHM, women caring for elderly relatives in the community). Choosing to be a SAHM because you believe this is the best choice for your children at this particular stage in their lives is a perfectly valid choice even if it's one which is undervalued by society.
What I do think we need to do as feminists is talk about how to restructure society to protect women against possible adverse effects of this decision. For instance, in the event of divorce (or even more so, the breakup of an unmarried partnership), SAHM are incredibly vulnerable financially. I would like to see some sort of legal recognition that where a woman (or for that matter man) has sacrificed earning potential and employability for the benefit of the family unit as a whole, in the event of a break-up they should get some sort of compensation for lost earnings. And putting more schemes in place to enable parents to re-train/get back up to speed once their children are school age. And making flexible working more the norm.
(For instance, one thing I'd really like a bigger discussion of is what the culture of full-time work, i.e. 37 hours plus a week, as the default, is mean to achieve. There's excellent evidence-based writing on this to suggest that a culture of long-hours presenteeism is actually counter-productive, see for example this summary of Robinson's famous "why crunch mode doesn't work" article, or the full article here. I suspect presenteeism actually functions as an institutionalised form of exclusion, exluding workers not because of lower productivity, but because they have demonstrated by their life choices that they don't put their employer above all other things in life. And that's something we can and should push back against).
As an aside, I think the "feminism is about choices" claim often confuses the necessary and the sufficient. A necessary condition of judging whether (in some mythical future society) feminism has been successful in achieving its aims would be that women have the same range of choices open to them as men. However, that isn't the same as claiming that a choice being made by a woman is sufficient to establish that choice as a feminist action. The action chosen could be neutral (choosing to have a cheese sandwich rather than a bacon one) or even anti-feminist (campaigning to restrict other women's access to birth control for instance).