Klingon designed ships have two nacelles. Romulan ships, at least the TNG versions have two nacelles. The nacelles aren't necessarily the issue as an in universe reason could be that they are more efficient, but it also bugs me that the general design language is the same across the board.

The Klingon ships don't mount their warp nacelles out on the wings - those are weapons. The warp engines are lateral arrays spread along the entire wing surface, and the impulse engines are on the central hull.