Why would you even have to wait until chapter 1189 to say imu ranks above him as a swordsman?
If you held this kind of position, wouldn't the sword of nothingness that withers everything in it's path be another obvious indication?
Or the sword that literally has aimbot via maki (Nemesis) , that can snipe anyone, you could have just said that makes Mihawks "hawk-eye" epithet redundant, and then mention him missing Luffy at MF or something.
All I'm saying is, you sure were slow in coming to what you now state is the obvious.