The Enterprises grew bigger with each generation and tended to be "the ship" of their time. The Nova has more in common with the Grissom than with a Constitution.
That sounds like you just followed the name lineage and not the design lineage.
Going from Constitution to Constitution-Upgrade is easy. Hull configuration stays the same with aesthetic changes.
From Constitution to Excelsior is where it breaks down. The configuration stays the same, but now the secondary hull including warp pylons are quite different. The warp pylons are bent 90 degrees lowering the nacelles to at or below the primary hull. The Excelsior is more the start of a new line than the continuation of the Constitution line. The Ambassador and Galaxy continue this design.
But if you look at the Nova class, she has more in common with the Constitution, straight nacelle pylons and warp nacelles above the primary hull. The Sovereign class would be more of a continuation of that line.
The Grissom class actually has more visually in common with the Defiant. Look at it from the top and the main hull's circular structure and aft section could form the basis of the Defiant hull. The Grissom like the Defiant also has both warp engines directly attached to the side of the ship.
Of course the Defiant has her unique engine cowlings and the Grissom has her underslung hull as defining characteristics. This goes back to Ziz's comment about a TOS-era Defiant-class which is what makes a ship say "Defiant"? Nacelles attached to the side of the ship just slightly below the primary hull could be a relative of the Centaur-class. But add those cowlings and <snap> it's a Defiant! (IMHO)