While it may be good for everyone in FC and you have a perfectly valid reason as a parent to want to change, it doesn't involve regulations like having a seat in the exit row but being unable to perform the required duties. There is no official US policy requiring that a family be seated together. Finally, most people that want to change seats could make the argument that "it's good for everyone in my cabin" - be it a family with kids that need supervision or just business associates traveling together that want to discuss business during the flight.

To put it simply, you have a desire to change seats and not a requirement to change seats. That is the distinction I was making.

Jim