SRL cleaned out the 147-pound division. He fought Benitez (who had defeated Randy Sheilds, Carlos Palomino and Harold Westin), Duran (who had defeated Palomino at welterweight), and Hearns (who had defeated Pipino Cuevas, Bruce Curry and Sheilds). On his way to winning the WBC title that Benitez held, he beat Armando Muniz, Andy Price (who had wins over both Cuevas and Palomino), Sheilds and Ranzany.
The very good-to-great fighters Leonard beat and the contenders they beat comprised the welterweight top 10 of the late '70s, 1980 and '81.
Also, the combined records of Benitez, Duran and Hearns at the time Leonard fought them was 141-1-1. There's no question that all three welterweights that Leonard beat in a two-year span are hall of famers.
Don’t even mention SRR. He fought in the era of eight weight classes with only one world championship for each division. If there were four “major” world titles and 17 divisions like we have now, he would have at least won one “world title” at 135, 140, 147, 154, 160 and 168 pounds (and probably 175 pounds).
You claim Mayweather “cleaned out” three weight classes, but what division did he really clean out? The closest was at 130 pounds -- where he did beat an old master and title holder (Genaro Hernandez), a fellow undefeated titlist (Corrales) and two solid contenders (Hernandez & Chavez) -- but he never faced Joel Casamayor or Acelino Freitas, both of whom were undefeated title holders when he was still the WBC super featherweight titlist.
The only stud he fought at 135 pounds was Castillo. The other two lightweights he faced were fringe contenders at best -- Victor Sosa and Phillip Ndou (who was really a 130-pound prospect). By the way, Paul Spadafora and Leo Dorin were undefeated title holders who reigned at the same time Mayweather was the WBC titlist.
At 140 pounds, Mayweather only fought DeMarcus Corley, Henry Bruseles and Arturo Gatti, who had picked up the vacant WBC title that was stripped from Kostya Tszyu, the real champ at the time.
At 147, he's defeated Zab Judah (for a title that shouldn't have been up for grabs), Carlos Baldomir and Ricky Hatton. That's not what I would call cleaning out the division. Antonio Margarito has defeated more 147-pound contenders ranked by The Ring than Floyd has.