The one that always jumped out was the Ambassador :
![Image](http://www.ditl.org/Images/sizecomp/ambassador.jpg)
Trace the lines of the windows on the front of the engineering hull. They curve downwards with the lines on the hull.
Then here's the Intrepid.
![Image](http://www.ditl.org/Images/sizecomp/intrepid.jpg)
Look at the back of the saucer - the decks curve noticeably up.
So is this just an artifact of those particular models, and not a reflection of the actual models? Or are we to believe that Starfleet engineers make ships with sloping decks? What would be the point of that?