I think that the reason that Luffy was with Z/S/J indicates two things.
- They knew Aramaki was strong and Momo with Scabbards stood no chance against him, so they gave them a "chance" to protect their country and they were ready to help the right time.
- We dont really know if Luffy told the others to come with him or it they went on to witness the battle because they knew Luffy was not fully recovered to take on an Admiral by himself and/or they wanted to finish him of quicker.
Ngl when Aramaki arrived at Wano i really thought that one or two "big shots" like Law/Kidd/Zoro/Sanji/Jinbe would be his hypetool but Oda did him dirty with his dumb promotion and the wifi diff goes on till this day when its obvious at least to me that he's just an overreacting character.
Change Aramaki with Akainu/Mihawk/Kuzan etc etc and i would agree about the wifi thing but he's not liike them.
Honestly even if Aramaki got past Yamato, the Scabbards, and Momo, he'd have to deal with:
Law
Kidd
Jinbe
Sanji
Zoro
Luffy
Kinemon
Kiku
Killer
Etc.
And I mean, Aramaki's strong.
No doubts about that.
But come on, he is NOT beating all of them back-to-back.
He may win against the majority or them in a 1v1 but not if they team up or he fights them one after another without a chance to heal.
He's dying.