Perhaps he looked so good on the flat because he enjoyed it. Enjoyed the change, the aw, the quicker shorter race, the flat track, the occassion, the stalls.
This notion that he just needs a clear round win the CH is, perhaps, just that.
Fact is he got round at punchestown and got hammered, he was not travelling well at all when he came down at aintree. Even at cheltenham he wasnt cruising with that air of inevitability or invincibility he once had. He could go to the CH and looks distinctly uninterested.