Isn't it kinda odd how Kishi compared Tobirama to multiple Hokages and made sure to show and stress that Tobirama is inferior to each of them? How very telling.
Even when he gives him a hype moment he makes sure to make him inferior by having the superior fighter show off.
Such as when Hashirama got a tiny bit serious after Tobirama
Or when he stated that the Professor in his teens was a much bigger talent than Tobirama
Or when he had him admit inferiority to Lord Namikaze Minato multiple times
Or when had him get stomped by Kinkaku and Ginkaku whilst Lord Namikaze Minato was toying with the Ultimate Tag Team
and prompting the fourth Raikage to declare there was never a finer shinobi
Or to have Hiruzen stressing about the 4th Hokage being awoken whilst not caring about Tobirama
But he didn't stop there. Kishi also had to point out how Tobirama got outdone by other shinobi, such as Orochimaru and Kabuto