Better Taijutsu.
Better Ninjutsu.
Better Intelligence.
Triple RDS in every hole.
As a matter of fact, Tsunade's taijutsu is on a whole other level as she managed to hold her own against multiple susanoo clones. What taijutsu feats does Hiruzen have that puts him above Tsunade?
Hiruzen may very well have better ninjutsu but all he showed us was fodder katon, fodder doton, Emna and RDS. Tsunade's Byakugo and her own slug summoning is far better ninjutsu IMO so Tsunade takes the ninjutsu category based on what old Hiruzen has showed us. I do believe that Hiruzen had a lot to show us but didn't since he was fighting immortals so he wouldn't waste chakra on powerful jutsus but I can't use hypothetical jutsus to raise Hiruzen's case.
Both Tsunade and Hiruzen are quite intelligent so I wouldn't say one is more intelligent than the other but Hiruzen's experience and wisdom puts him above Tsunade IMO.
RDS wouldn't work if Tsunade has Katsuyu summoned since while Hiruzen is holding her, the slug could attack Hiruzen thereby killing him.
Hiruzen's score surely speaks for himself, but the extent of his powers is merely hype, Tsunade takes this featwise.
Doesn't Tsunade have a higher data book score compared to Hiruzen? You seem to ignore Hiruzen's hype for the most part but when it comes to Tsunade, you rush to Hiruzen's bandwagon. I smell some bias.
Tsunade stomps mid difficulty at most.