I'd keep the saucer, I feel like that's the most distinct element of the design. If you change it, it won't really feel like a Galaxy Class anymore.
One thing I've always liked was the way the nacelle pylons looked in some of Probert's earlier sketches, like
these. Specifically how they're more forward-swept and come up at a diagonal, as opposed to the L shape of the final ship. I'm not entirely sure it would translate to 3 dimensions, though. For the nacelles, I think a more vertical nacelle shape could work, something more like the Refit. Instead of echoing the shapes of the saucer and secondary hull, it would echo the shape of the neck and pylons.
I think detail-wise I might take some cues from Voyager. Subtler hull paneling, offset by areas of high detail. Sensor platforms, a distinct secondary deflector, saucer torpedo launcher, more variety in windows. For the main deflector I think I'd do something like the Ent-E, more intricate detail with amber lighting (not bright yellow). I like the Ent-E lifeboats too, but I wonder if they'd clash. The saucer impulse engines wouldn't cut into the oval of the saucer, but be thin on the edge. Sort of like if the sensor band lit up red on the back of the saucer, but thicker. I'm kind of rambling so I'll stop there.
