Imu has 6 top tiers directly under him. Luffy needs more than Zoro, Sanji, and Jinbe. Hence Loki and Yamato, both who got invitations to the crew, will likely inevitably join in the end so that Luffy can compete with Imu.
That way you can have
Luffy vs Imu
Shanks vs Garling
Zoro, Sanji, Yamato, and Jinbe vs 4 gorosei
Loki vs Shamrock
Obviously Luffy will have other allies. But the direct subordinates of the main villain tend to be defeated by SHs. Hence I find it likely Luffy will gain final additions to the crew to rival Imu.
That way you can have
Luffy vs Imu
Shanks vs Garling
Zoro, Sanji, Yamato, and Jinbe vs 4 gorosei
Loki vs Shamrock
Obviously Luffy will have other allies. But the direct subordinates of the main villain tend to be defeated by SHs. Hence I find it likely Luffy will gain final additions to the crew to rival Imu.
