Why Domi Reverse was created by Oda

Inspired by this comment that basically said that Nika is the reason why killing in domi reverse turns someone back alive it made me think that if thats true then that could be the reason why shanks waited for nika because otherwise he would just get turned to a slave.

That ability is also the reason why Shanks stopped Loki who probably wanted to fight Imu.

Now to my title: I think Oda created domi reverse because he wanted a reason for Luffy having to fight and surpass Shanks. He saw the problem that Shanks was too strong and he thought that it would be too easy if Luffy and Shanks just showed up at Marijois together to tag team Imu.

He was looking forward to that fight from the beginning of the manga probably but plans changed and Shanks is not an egoistic pirate who would fight Luffy for the one piece as a rival (turns out he doesnt actually care and is a saint). He also doesnt want shanks to be evil.

What is the solution? Yes, domi reverse. This way he gets that luffy vs shanks fight but at the same time he gets Luffy and the saint good guy Shanks tagteaming imu. He can keep his cake and he can eat it too so to speak.