Let's not open the historical precedent can of worms. Do that and you quickly find out that nearly every weapon was specialized in specifically countering the armor of its day, and a third of the armors in the book never existed. To say nothing of dual wielding at all being pretty rare historically.
Rather, let's ask if there's fictional precedent for ways to make it look cool. And in that field, I think it's a bit thin. Most fictional dual wielders either go for a matched pair or a big/little pair. So scimitar and shortsword does come off as a bit of a mechanical incentive over an aesthetic one. How much so may depend on how useful a free off-hand is.