You know, the Defiant's scale was actually correct.
I have never seen a Star Trek game that has a Cube scaled correctly.
Cube's are 3 x 3 x 3 kilometers, or 27 CUBIC KILOMETERS! They're GIGANTIC.
The Enterprise-E is 700 meters long. A cube is about 4 times longer, and of course WAY WAY wider and taller.
The Defiant is a puny 100 meters long. The cube is a good 30 times longer, and probably a good 300 times taller.