For those who are unaware, Oda revealed in I believe Data Book Yellow that he heavily based Whitebeard on a man he knew, a gruff old bartender dependent on oxygen who liked to yell at whippersnappers and tell old war stories. Apparently the guy was delighted when Oda told him, and with that retrospect you can just tell in how Oda presents Whitebeard he respected him a lot.
There's a quote from Oda in the SBS for volume 82 that suits Whitebeard particularly well, and it becomes especially poignant when you know he was based on a real person
"I love me some old dudes! I feel like age adds a new sense of depth to characters, both male and female. One Piece has tons of really interesting old people! But in the real world, age tends bring people down to a weaker state… and I've always disliked how there are some young people out there who just can't have a little respect for these aged individuals because of this. So with One Piece, I've brought to life one of my countless fantasies: which is for there to be super cool old people who've maintained their strength throughout the years.One day, you also will grow old. It'd be great if all of you could remain just as strong as the One Piece oldies are!"