They didn’t want to fire her, but she did want to quit. She wasn’t happy with the direction they were taking her character. I wouldn’t be surprised if she also had issues with the same guy McFadden did. Jadzia was killed off because Berman wouldn’t let Farrell switch to being a recurring rather than a regular, which may be what you’re thinking of.
Something to consider with those two images is that they’re different angles. Your first image is of the underside of the ship, while the second is the top of the ship.
Also, the texturing and nacelles are different between the two, but the body and saucer seem to be structurally the same. Still a long-boi even with the slightly shorter nacelles.
The Excelsior-class is one of my favorites. A bit wonky from a top-down view, but gorgeous from every other angle.
The Sovereign-class continues the general aesthetic of the Excelsior, but for the TNG-era design style and fixing the problem with high angle views.
The Valdore-type warbird from Nemesis is probably the best thing about that movie.
The Klingon D4 from Into Darkness is similarly one of the better things from that movie.
The NX-class Refit is also just shockingly pretty. Makes the original look incomplete.
Not canon, but I love the original “Long-boi” Discovery design. It gives off some very cool art-deco retro-futurism vibes. Not very classically “trek” but I love it nonetheless!
That is the canon design for the Discovery before the far future refit it got.
I’ve heard that Data was originally going to be a science officer and the blue uniform didn’t work with his makeup, but I don’t know whether or not it was true.
I’m pretty sure he was also the only command division officer on the bridge after they gave him command. At least in theory, due to differences in training, a lieutenant jg from the command track may be better suited for acting captaincy than a full lieutenant from science, especially with a decidedly non-sciency mission like flinging a warship at a wall. You need that dash of crazy that Starfleet’s command officers tend to have.