The biggest hangup I have about your 9" model is that it ends up three times the height of a warlord. The differential between each step of the three smaller classes is what, 3/4"? Jumping from the warlord to your Imperator is a leap of over half a foot, in epic scale no less! That just doesn't jibe with me. That's too huge of a gap with nothing in between.
I think that the relative scales of the actual epic models are pretty right on. I liken three smaller ones to a man, woman, and child in size and relative power. The Imperator at fully twice the size of the man is a veritable giant in comparison. If anything, it's the FW titans that are too small. If the FW warhound was a slightly more robust 14", the Imperator would come out at about 4 feet tall.