Hagler vs. Hearns. The intensity from round one and the punches landed and taken.. Both guys took hard punches and brawled. Rosario vs. Ramirez was great, and I put that fight on youtube, but it was Rosario coming on strong and then losing his stamina and being blasted out.
This article explains why Rosario change from boxer puncher into a seek and destroy puncher. https://www.si.com/vault/1984/03/26/569048/rosario-turned-on-the-juice
Hagler Hearns is a fight between two super elites and fought at a pace you never see between other fighters nor fought at that kind of level remember; Hagler was the numberone pound for pound fighter in the world probably since he won the title and certainly by 1982 while Hearns had just peaked and was regarded as either the number one or two p4p fighter Ramirez - Rosario is memorable but not as well fought or as intense
Hagler-Hearns. Ramirez-Rosario 2 was a terrific fight in pure action terms but with Hagler and Hearns it was two all-time greats and world champions in their primes fighting for the undisputed middleweight title and that elevates it to a different level to the Ramirez-Rosario fight. The hype for Hagler-Hearns was immense and that it managed to live up to the expectation is a big part of what made it so memorable. That's why it remains the gold standard for short fights.