I don't compare Tyson to Johnson - I compare him to himself in early rounds. Johnson wasn't a high volume fighter and we all know this. I'm basically saying that Tyson was very easy to tie up inside and Johnson would take advantage of it. He'd push him, grapple him and show him. Tyson could get tired because of that, you probably know how exhausting grappling can be. Besides, Johnson was the master of clinch fighting - he could punish him inside in a way that Smith simply wasn't capable of. He wouldn't have done that early because Tyson was much more fresh.
Bonecrusher wasn't in anyway an oaf, he was an explosive technically sound big puncher with knock out wins against Bruno, Witherspoon and Weaver. You should watch some of his wins before making such comments about him.
I've seen his fights against Weaver, Ruddock, Tyson and Bruno. He was very strong and he indeed had decent technique. He was also slow as hell and didn't have good defense. Calling Smith explosive is the definition of era bias. I really like Smith as a fighter, because I like smart and slow punchers but he's extremely limited. You know that he lost to Marvin Frazier, right?