Maybe Xavier-Stora still felt it looked cheap, like he did two years ago. *shrug*
I can't say I'm familiar with the poster. He thought other Marvel films looked cheap? Two years ago the film was only in preproduction. The other thread lasted 22 months and covers that whole development span. Did he think spy photos and the such made the in development film look cheap? I don't recall his posts in the thread off hand.
Maybe he can answer. An 'F' grade just seems contrary.
For perspective I'm no big fan of Avatar but I'd never grade it an F.