If he's the pinnacle of power(nik's behavior), then why did Imu doesn't view him as a threat? Why did he had to stole the poneglyph and to avoid BM? Why does we don't even see or have a statement he defeated a notable character in 1v1, instead of rivaling another characters?
This is the same kind of argument which made people think Roger defeated Xebec in 1v1 before GV flashback.