I agree it should be scaled down somewhat. The "Space Dolphin" is also very large compared with the existing Advent capitalships, yet I kind of like it. The Corsev fits in very nicely I think, I wouldn't want to see it resized.
Yet because the design fase of Rebellion is long gone, it is very unlikely to see the models tempered with. Maybe some modders will scale it down once the game has been officially released though.