I went from AW 2 to AW 4 and I think you will be pleasantly surprised by how much improved AW 4 is. Much faster to load apps and updates, screen size increase, speaker, Siri, digital crown. I also really like the slimmer profile on the wrist, it's not as tall as AW 2. I still make use of my 2 in certain circumstances so it's certainly still very much usable, I'm sure your kid will enjoy it. Here's hoping you enjoy the Series 4 as much as most of us do.