The Enterprise-C bridge as seen in "Yesterday's Enterprise" was very obviously a "set of the week," something not up to par for a "hero ship."
Although the episode doesn't suggest this in any way, I like to think of the YE set as an auxiliary control center or battle bridge, with the ship having a much more "hero-worthy" main bridge.
Back on topic, I'm very interested in the continued evolution of Probert's exterior design for this ship. The secondary hull and nacelle struts are the big remaining mysteries of this design.
Yes, i can't wait to see the final result. I'm guessing the ships hull detail will be the same as the current ambassador, since for me the basic shape was the only thing that needed altering rather than the actual skin detail/colouring, i always felt that they got that one about right in the sense of making it a mix between the exelsior/galaxy