Open-world games are difficult to make very well. I find myself unimpressed with anything open-world simply because of the lack of life. 10 people in the village, okay. How underwhelming. Leave the village and suddenly 100 bandits are trying to brutalize you.
Valve wouldn't attempt it with...
The cuteness is only so that they blend in with honest society. They never truly die. Instead, they leave their old bodies behind in order to become beings of pure bunnetic energy, feasting upon the souls of men working dead-end jobs and winos without booze.
So, become a scout. Pull out your trusty bat, and bludgeon all the other scouts, pyros, snipers and demomen. Then capture their control point. That'll show your dear ole' dad who's the best scout.