My eyes want the lower sensor dome (or whatever the doohickey is that you added to the centerpoint of the saucer) to be an "outie" instead of an "innie". You already have the wraparound scoopouts on either side of the dome assembly... surrounding the sensor dome with another
scoopout seems like too much of a good thing.
Regarding the aforementioned scoopouts, I have a question: Is the purpose of these features to allow for vertical portholes on the underside of the saucer? If so, the Grandeur
is much larger than I thought, because those scoopouts don't look nearly deep enough to be the height of one deck at the scale I thought your ship was designed (which is about how deep they'd need to cut into the hull in order for eye-level portholes to be accomodated).
Don't touch anything else. The Grandeur
is one of the most creative and original non-canon designs I've ever seen, and you should be justifiably proud of your work.