How you can have Tyson on the list at #21 and not even have Holmes listed is confusing. Holmes' longevity and considering his advanced age when he won the title, 28/29, combined with his seven year reign and also being greater than Tyson as a heavyweight surely gets him in your top 25? So many fighters to choose from, so maybe he's simply been forgotten. If Tyson makes your list based on popularity and going about his business with distinction, how about Lopez with his undefeated record and supreme technical ability.
Aaron Pryor would not make my top 25. Benitez might just, not too sure... Jones is much too high. Mayweather a little too high. Tyson should be below Holmes, Foreman and Frazier... I'd have him below Liston too.
Yes definitely you should have Ortiz rated higher. Ortiz was a complete master who had craftiness, chin, skill and one punch ko power upon occasion. He was a sort of Barney Ross type of fighter in terms of careerlong toughness, but with more pop on his punches. Ortiz was a master.