Conformation wise, I think he is too wide....he has a gait instead of a smooth stride, for being such a big dog he moves well but I have seen him out run because of it too. He does however have a nice 'ice box' build to him in the sense that his top is straight, I am not a huge fan of one's rump being higher than their shoulders but that probably reverts back to the days of livestock judging

it is just a habit and he has a nice deep girth so even though as big as he is he doesn’t get winded easy like some.
Personality, I wouldn't change him. He is one of the most unflappable dogs I have been around but he does have that tick for strangers and their dogs but I think that just comes from being hunted 'alone' for his entire lifetime but he is also sociable….which is something this younger generation we have now lacks.
You are right, too much grit and bottom is a bad combination….but a vest on one that has a lot of bottom is a bad combination as you run the chance of overheating / fatigue so it is almost a double edged sword.
We bred Goober's sister who is strictly bay to a dog exactly like Goober (minus personality / add squirrel factor), the outcome was Chance who will beat the bushes at 250 to 500 yards and will bay like crazy by himself but put another dog with him and he becomes an ear chewer on anything over a hundred or so pounds....which to me shows he isn't fully committed and there is still some hesitation to it, which IMO will wind up getting him hurt...I would rather have one that is strictly catch so they can learn their 'style' or strictly bay, I can tell you I am not a fan of the semi-committed crowd. He is not sociable but will come to you if called albiet he cowers.