Interesting question and interesting way to pose that question. I'm not sure you are asking how "good" Deontay is/was as much as you are asking how he would have faired against the top heavies in the sport. The difference, as I see it, is that one fighter can be "better"- more skilled, versatile, fundamentals...etc., but still lose to a more athletic, mentally strong, harder punching...etc., opponent. Essentially, I can practice my fundamentals in basketball daily, be extremely skilled on defense and offense (shooting, dribbling, passing...etc.), and get blown out by a 6'9" player who rarely practices and relies on his athleticism, height, explosiveness...etc., to overcome my skill advantage. So, I'm technically a "better" player in that I can do more but his physical advantages are too much for me to overcome.

If we look at it in terms of good being skill- Deontay comes in behind pretty much everyone on that list as he really only has a straight right (his jab, right uppercut...etc. are used sparingly at best) and absolutely ZERO defense, footwork...etc. That being said- the guy is mentally tough, has heart, is VERY TALL, and has a cannon for a right hand. I don't see the MUCH smaller Marciano surviving a solid right and I don't see him having the defense to avoid it for 12 rounds. Most of those older fighters like Jersey Joe Walcott, Ezzard Charles, and Joe Louis were LIGHT YEARS "better" than Wilder, but I'm not sure anyone outside of Joe Louis (and maybe Jack Dempsey) would be able to overcome Deontay's size advantage. Liston was a bear and extremely skilled with a great chin, so I agree that Sonny would use superior skills and physical strength to break Deontay down over 7 or 8 rounds.

The crew from the 70s is interesting- I think Ali is way too fast and good to let that right hand land often, and Wilder's horrible footwork would make him look awkward in there. Foreman is a beast and would walk through bombs to push Deontay around and literally beat him up- you had to be mobile to beat that version of George (and the older one as well, I guess). Joe Frazier is interesting because of the size difference and seeing what Foreman's bombs did to Joe- the difference I see is that Wilder won't have the physical strength that George had and won't be able to keep Joe at the distance necessary for his big right to land. Frazier was also a murderous body puncher and inside fighter and I can see him breaking Wilder down and stopping him in the later rounds. I think Deontay stops Ken Norton (he wasn't his best vs. punchers), Jerry Quarry...etc.

In the 80s I see Holmes being too good and having too many options (great chin, defense, speed, jab...etc.) for Deontay. I'm not sure he would stop Wilder but I think that Holmes would make him look silly as there would be a noticeable gulf in terms of skill between the two- and Holmes did the resurrection routine against Ernie Shavers like Tyson Fury did vs Deontay. Tyson would be similar to Joe Frazier in my opinion, but a little faster and harder hitter (ESPECIALLY with the right)- I think he gets inside and brutalizes Wilder who wouldn't be able to use short hooks/uppercuts inside and/or keep Mike outside with a hard jab. Depending on the night he faced them, I also don't see Deontay beating Dokes, Tubbs, Witherspoon, Tucker, and Page- as long as those guys came in having trained and not high on coke.

The 90s crew is interesting- Lewis, Bowe, and Evander are too much for Deontay. Think of the skills those three had and the various ways they won fights and then ask if Wilder could do anything those three couldn't other than being 6'9" and possessing the most devastating right hand in history. On the right night Ray Mercer is a horrible match up for Deontay, as are David Tua and George Foreman. That being said, I feel like Wilder matches up well against Tommy Morrison, Herbie Hide, and ESPECIALLY Michael Moorer.

For the current crop- I think Usyk and Fury (obviously) are too good for him and would only lose to him off a lucky shot. I don't know Joyce so can't comment on that match up, but feel that Whyte is equally inconsistent as a fighter and around the same level as Deontay. I wouldn't bet on that fight or be surprised if either guy won. AJ would be a great fight and style match up- I still think that AJ is the "better" fighter (athlete) and would win early vs Deontay, but Deontay has the mentality of a fighter and would eventually catch AJ to stop him. I would pay $100 for that fight easy- despite both losing and showing their limitations.

So, to sum my POV up- Wilder is not a "good" fighter, but he is mentally tough, tall, and has a big enough punch to make every fight interesting and dangerous for any opponent. I do feel that he benefitted from a not great heavyweight division and would not have been a top guy in previous decades.