Seems to me that it's all about choke, shot pattern, range and skill.
And judgement.
That's it in a nut shell.
We killed a lot of deer with buckshot when I was a younger man and when virtually everyone in our region of Alabama were running deer with dogs. Buckshot's reputation for wounding deer can be divided into 3 categories in my opinion. None really the fault of the buckshot.
1. People not patterning their shotguns to see what kind of patterns they are getting with a particular choke and shell. Lot of people back in the day were flying blind so to speak with no real clue what kind of patterns they were flinging.
2. The fact that we were shooting at running deer with a pack of hounds hot on their butt. Not taking a swipe at dog hunting here but it's just common sense that shooting at moving animals is going to result in more bad hits than shooting at stationary ones.
3. People not respecting the limited range of buckshot. It's hard to believe that something which can be so lethal at 30 yards can become pretty ineffective by the time it reaches 50 yards. I always kept my shots 40 yards and under. Also few people had the will power to let a really good buck pass by just out of buckshot's effective range without lobbing a few spray and pray shots.
I don't use buckshot anymore. We no longer run deer with dogs and if I'm going to limit myself to 40 yards and in I will typically have a bow in my hands these days. But if I needed or had to use it, I would pattern my gun; respect it's range; and kill deer just fine with it.