The problem in my area (legal) was certainly that the whole system was set up to eat as much of your life as possible. Your salary is a fixed cost and you are judged by how many hours you record in a year. The chats you might have with senior partners take place when you bump into them at 7/8/9 pm, as earlier in the day they are rushing to meetings or on conference calls.
Pre-children, most men and women accepted this. I worked crazy hours. And in many ways they got crazier post-Blackberry. I once had a colleague get cross because I hadn't joined a conference call he had organised on a deal on a Sunday. A conference call he had simply notified people of by email a couple of hours earlier.
Post children, I had to carve some time back, or I would never have seen them. But even though I was earning less and working almost as much, the perception was that I wasn't on track any more. And I didn't have those key networking conversations and trips to the pub.
And if you are the boss of a firm like that, I get why you want the father who will work all hours with no boundaries and not me. So I think that the changes need not to be focused on women with children. It needs to be about people generally carving more life for themselves. Because that's the only way large numbers of women will want to play the game. (Although why mothers feel pulled towards work/life balance and men don't is a whole other post).
Interestingly, I have had two conversations with partners at law firms recently about how they have issues finding people (not women, anyone) who wants to make partnership. The rewards aren't seen as there and the path to get there is seen as too long and too unpredictable. If this genuinely becomes a succession planning issue, law firms may have to change their ways.