[Silver-Throne]

In my opinion respectively,I say all of the Hokages are strongest in their own ways and strengths. The titles they earned is not for earned for nothing; it is with sweat, blood and hardwork.

Spoiler for 2 examples : The Yondaime and Nidaime:

For example: The Yondaime is known as Yellow Flash because of his ultimate signature jutsu, the Hiraishin(not the Raiton). Meaning he is the fastest ninja and deadliest once you`re in his range(So watch out for his Hiraishin kunais in battlefield). He fought Obito and Kyuubi at the same time

The Nidaime, I can say that he is known for his mastery of Suiton(Water Release), creation of Edo Tensei, swordsmanship(well duh, it`s shown in manga somewhere set in Clan Wars) and space time techniques. He also contributed the foundation of Leaf, his ultimate legacy for the incoming generations(Do their hairstyles look a bit similar between the fourth and him? Never mind). First War : He fought the whole squad by sacrificing his life just to save Hiruzen and his team mates(It`s in his calculations: meaning one of them must stall time. So, he volunteered himself and died fighting)