For me, the pylons and nacelles tie for worst, but while we're at it, the secondary hull is all out of proportion. The neck I can live with and frankly I always thought the neck of the original model was too flimsy to really work. Hey, even in space there are Newtonian forces to be reconciled with an a skinny (to paraphrase Fred Blasse) pencil-neck just won't cut it. Saucer is OK- probably the best part of it.
Look, I just can't see them putting so much effort and hype into this model to just trash it in the course of the film and surprise us with a different one later on. The Enterprise from TOS will never be seen on film again- it just wouldn't make any sense after this one.
Again, I'm not as disturbed by the ship as I am by the historical changes made in the storyline. If we are to accept those changes, then the ship should be the least of our concerns.
"Stop it? I'm counting on it."
"But not because you threaten me. I'll pay you because... it's my pleasure."