... Like when Kaiosama made goku chase a monkey around the planet to train? Or when Goku's son decided to dress as a Sentai hero to fight crime?
I don't think it ever really changed.
Let me clarify that as an older person I still enjoy it, but I'm not going to pretend dragonball is "serious". I liked Avatar too and felt it had good writing and animation, but it was still very much a kids cartoon. It's still about a guy who shows he "powers up" by changing hair and then proceeding to yell for half a book only to use his "final gambit technique" or have people "believe in him" to win.