I like peak Hearns at 154, especially if it's over 12. They will always have great matches and this would be no different. Hearns took a bit out of their initial encounter (clinching, pacing, experience) whilst SRL was already extremely well rounded. Hearns was also the naturally bigger man and a bit stronger at 154.
What people don't realize is that Hearns was still developing into his body at Welterweight. He was dangerous nonetheless and one of the top H2H Welterweights ever, still. But he was a better figher p4p at 154 than 147. That's when he finally grew into his frame and settled into his natural weight class.
Absolutely. 154 imo was the best Hearns we ever saw and only some hand injuries held him back from doing even more.
The 89 fight was similar to the first with Hearns early and Leonard coming on late. Difference being Leonard was much more susceptible to getting caught at that point. I think if that was a 15 round fight that Leonard would have stopped Tommy again. 84 was probably Tommy's absolute peak and over 12 I think he'd beat Leonard at 154. Over 15? Tossup IMO. Hearns if it's a decision, Leonard if there's a stoppage.
I think the two fights taken together give a strong indication that Leonard in most cases would stop Tommy over 15 rds prime for prime, at least below LHW. Over 12, it's a different story however.