Back on the topic... for once I like All Good Things. Didn't felt quite like a series finale, but then, it would have been hard to give a sense of closure as there was no major story-arc in TNG (something I feel lacks).
I had no trouble either with the three-nacelle design. Maybe an even number of nacelles generates a decent warp field, but other nacelles could give an improved, if less stable warp field, and technology evolving could have allowed for such a design to exist. Or maybe the Ent-D refit was just an experimental ship.
To be honest, the ship design I didn't like was the Defiant. Even or odd-numbered, I like a ship's nacelles to be far from the hull. The Defiant always looked to me like a Trekified Millenium Falcon.