you right he was the one stongest hokage.knowing 1000 jutsu tht crazy i dont care if have speed or growing tree or make water out noting.when faceing a person tht over 1000 jutsu you really in for a fight.not a push there almost something for something.According to manga(Iruka) and databooks(Kishi)
Third hokage prime = strongest hokage
Knew over 1000 jutsu just like kakashi , had a counter for ever existing jutsu in konoha , at one point knew ever existing jutsu in konoha
Minato > old hiruzen.....
Which is why he passed on the title of strongest ninja in the vilage to him... when minato died he got it back