I think it's looking too deep into it; it's just a design quirk. By that token, why ar ponies in earlier generations exactly the same size and body type?
There's also the traditional design quirk that male characters are taller, female characters are shorter, and so on,
The hospital final fight in The Last of Us.
Dragons in Dragon Age 2, and that golem in Deep Roads, I swear to god! Easier with Mage Hawke.
Ah yes, Necron! Cheeky bugger.