Why are people ignoring the fact that Tsunade had her chakra replenished by Karin (who is an Uzumaki, and thus has vast amounts), whilst Sakura had been healing the shinobi alliance (and had summoned Katsuyu) by herself and was obviously close to running out.
While there's obviously still a gap in their medical expertise (though certainly not a huge one), Hashirama commenting on Sakura's strength can be easily be construed as Kishimoto indicating Sakura has at least surpassed Tsunade in that respect, which is fine and actually pretty common in the manga. Sakura doesn't have to surpass Tsunade in every possible way. Sasuke still hasn't surpassed Itachi in genjutsu though he has surpassed him in a lot of meaningful ways. The same goes for Naruto who hasn't surpassed Jiraiya in seals.
Whether the haters like it or not though, Sakura is easily Kage level and has by now probably surpassed Tsunade.