I mean he knows over 1000 Jutsus, knows all 4 Elements, and became a jonin at such a young age. Hiruzen nor Kakashi had any special Kekkai Genkai or Special Eyes (as a Hokage of course). But is there a difference between the two? Well other than the fact Hiruzen is a Sarutobi and Kakashi is not lol
No lol You said all 4 but there's 5 basic elements plus there's yin and yang chakra. Kakashi only have lightning, earth, and water by the manga and the 4th that you mention is fire which was only shown in the anime. Kurama used fire in the anime but not in the manga so we can't just count that. Hiruzen have all 5 elements. Hiruzen as an old man is stronger than Kakashi with the Sharingan. Hiruzen as an old man was said to be the strongest of the 5 Kages in part 1 by Kabuto while talking to Orochimaru so that's Oonoki, A, Gaara's dad who recently was killed by Orochimaru, and Mei.
Hiruzen learn his jutsus from his skills with no extra tool while Kakashi learned his 1000 jutsus by using an extra tool in the form of Obito's Sharingan. Hiruzen was able to know what jutsu would be used by seeing the hand seals and can breakdown jutsus such as Juubito's TSB attacks just by seeing it. He didn't have the Sharingan that can read movements, see through jutsus, see chakra color or anything. Prime Hiruzen was said to be the strongest Hokage which puts him over Hashirama which Kakashi is no where close to