Bro, Shanks had to step in because Ryokugyu was about to get serious and he would annihilate them unless Luffy and co would intervene too.
Check how pissed off Shanks was that Ryokugyu wanted to go all out. It's real and it's there.
Yamato is overrated as fuck.
Check how pissed off Shanks was that Ryokugyu wanted to go all out. It's real and it's there.
Yamato is overrated as fuck.
Shanks was pissed at Greenbull for trying to attack the new Gen when they are all still recovering, that's what Shanks said.
Literally when he is pissed off, he says " Does the New Era frightens you that much"
Yamato was not allowed to fight, plot saved Greenbull, not even once he did even hurt Momo or made Momo complain of pain while he only managed to catch a Base Yamato was heavily holding back and not fighting.