I agree it would be better all round for dads to have more of an idea about what is involved in taking care of a small child and running a household. I think dad-child relationships would only improve with dads being more involved in their care.
It won't change overnight. We have CENTURIES of conditioning telling us what a mother's role is versus a father's role. There are external and internal barriers for mums and dads in terms of how they negotiate parenting/work roles. For a start, even where dads can request flexible working atm, they rarely do. There is a structural assumption that it will be mainly women who ask for it, and it can be seen as more damaging for a man to ask for it than woman, in terms of career. And many men see childrearing/domesticity as a bit emasculating. It's not just a case of 'will women let them take over more.' And no, a lot of blokes won't want to do more than a bare minimum of hands on parenting. That's sexist behaviour which needs to change.
I think the SAHDs who take on that role at present often have to be quite brave about being the sahp in a world that is very mum-dominated and feminised. And vice versa - for those of us mums who have taken on the role as main breadwinner in the family - well, I can't look at other women in my extended family who have done that before me. Sure, they've always WORKED - but they haven't always had careers, and they certainly have not been the main earner. I'm the first one. It's impossible not to internalise these things in some way.
I think it's oddly punitive to keep saying 'well, ladies, it's up to you to decide what you want! make your minds up!' For my mother's generation, it was generally accepted that if you really really wanted a high flying career, then you didn't have children (if you were a woman, I mean. obvs as a man, you just had a wife...). A generation later, I feel personally like I have been raised and educated to 'have it all', and that I should be able to have a career AND children - but the devil is in the detail, and the small print has got some nasty clauses! (like, whenever the media talk about about women and work, it is always assumed the mum can only work when SHE earns enough to cover HER childcare costs.... again, WHERE ARE THE DADS.....). Rome wasn't built in a day, I guess.
I think btw it is absolutely fine for mums to decide that actually they do want to do the hands on parenting themselves, and are happy to give up a place at work to do that. I just know that by adding more dads into the mix, we acknowledge that parenting is not just carried out by mums, it would inevitably become more valued, and we would all have a greater degree of flexbility and genuine choice. The sahm/wohm 'debate' is a smokescreen - it hides the continuing absence of dads in the whole equation.