I don't like the Duran who climb up the ring that night against Hearns. The moto city cobra was obviously too much for Roberto to handle. In case of a rematch, a post-Hagler Hearns will fight a post-Hagler and post-Hearns el cholo. In my opinion, Hearns will still beat Duran if Duran showed up as the same fighter like he was in their first match. Duran has an underrated boxing skills, he can box but as you have said outboxing Hearns was not a good idea especially Hearns has an arm length advantage unlike when Duran fought Hagler where Duran utilized his boxing skills because Hagler is not that tall compared with Thomas. So a rematch between the two is interesting but I am still gonna give this one to Hearns. Nice question!
Add: In my opinion Duran rushing towards Hearns will not work either. Duran outboxing Hearns is better, he (Duran) had just to improve his defense in order for his outboxing plan work better.
I think Hearns was just too strong.As much as i love Duran,Hearns would have overpowered and destroyed him again!