Great post OP, this topic comes up here a lot and there are mixed results.
Personally I hate kids, and even more so I hate PARENTS! I could go on for days about how annoying it is that the world is set-up for "Families" and Childfree and single people are on the outer especially as you pass 40.
With that said a few days ago I had a debate with two child-positive childfree people on here, one had nephews and nieces like you and the other was a child speech therapist so they both had different insights than I do.
Personally though I don't want to be around kids ever, I don't want to hear about the weekend of driving kids to swimming and sports. I don't want to know about the mountain of washing or the endless cooking or any of that nonsense.
I''m a free spirit and I shall continue to paddle my own canoe