That ship sailed though. They've already been depicted as tall, and by game rules Superheavies are a whole level taller. What Sentinel's done is to shrink the model down as far as possible while paying some 'lip service' to both previous rules and art.
I agree that the ship has sailed, but more because the Omega is the size it is, rather than because of the game rules compared to the Atlas. (And the Omega is beautiful, so I will be happy if they roughly match.)
Based purely on the game rules, the Atlas and the scorpion are both the same height. The minis (rightly) disagree.
Personally, I think I'd make it 1-3mm shorter than the Omega, but that is so fine a gradation as to be nit-picking.