I don't have children, so I can't comment from that angle, but I have owned and then parted with both reissue flaps and a baby cabas.
I never found the reissues comfortable to carry because of the type of chain they have. I love the way they look, but I never enjoyed carrying it. I felt like I was always fussing with it. So I didn't regret parting with mine.
However, I parted with my baby cabas and MAJORLY regretted it. It was hard to replace it (though I finally did) but in my opinion, that's such a great, comfy, practical bag and they are pretty hard to come by. I think the cabas looks amazing on too. it's not as beautiful to look at when it's just sitting there, the way a reissue is, but I think it's a bag that looks great on everyone.
Of course, the most important thing is what works for your new lifestyle! That's just my experience.
Good luck deciding and congrats on your baby!