When you mentioned that you BP love to have his cheeks rubbed that is human emotion, the truth is your BP does not love it, and really does not care, he only tolerates being handled.
I think that is great to have an opinion but I also know that if I was in the OP's shoes I would consider the opinion of peoples that have enough experience to actually have experienced the pro and cons and you are not there yet. Trust me I love those animals, however I also know the cons of those animals.
Bottom line if a customer or potential customer casked me the same question than the OP did (to sum it up is a BP an ideal snake for a 4 year old?) I would not recommend a BP as a first snake, yet BP are what I do and that is because this is what I do that I know there are better snakes out there to fit the bill.