I was thinking as to why Dragon's personality is so different from his dad's and son's - I mean, there is clearly a reason for it, Oda is cooking up something tragic, and by the time God Valley took place, well, he would've been 17. Given how trauma works, if Oda wants to go down realistic path, Dragon might've been traumatized by what he saw there (I am still going along with the idea of him also killing some God's Knights too - it just feels badass, and it would make sense that it was not made public since WG probably wouldn't want this kind of info out Garp could always blame it on Xebec and such)

Think is, the trauma actually might've been pushed back for some time while he was younger, which is where I think Oda might bring the fucking gut punch - his trauma might've resurfaced fully when Luffy was born. Seeing his child in his arms might've reminded him of all the dead children at God's Valley.

I just think that not having Dragon there would be such lost opportunity - and you bet that even Garlic wouldn't go jack shit because prime Garp is right fucking there.