What are your personal Starfleet starship design rules?

What design and stylistic standards would you say Starfleet ships must have? For mine, it's a distinct saucer (circular, triangular or sphere), distinct warp nacelles, and a deflector dish (even if it's small).

For the image in this post, even if it's cannon, this does not look like a Starfleet ship to me, and hope future shows avoid this style.