>>28131554Physical has access to a wide range of boosting moves (Swords Dance, Dragon Dance, Moxie) as well as a tendency to have highly reliable high power moves with a draw back. (Close combat, Double Edge, Earthquake)
This means they're either an immediate powerful threat, or have the ability to boost into insane powerhouses.
Burn and intimidate are intended to neutralise, dissuade or force these boosts, or to cripple a powerful but non-boosting physical force.
Special attackers have a very limited access to boosting (Nasty Plot has low distribution, Calm mind only boosts one stage). This inability to boost in a meaningful way creates a situation where special attackers provide reliable damage, with less potential for massive damage than physical attackers, but also no way to stop it by debuffs.
Others things to take into consideration
Confusion damage hits physical side,again playing into the risky boost phsical, reliable special paragdim
Chansey/Blissey has always existed in the competitive singles enviroment to neutralise special attackers.
There is a tendency for Physical to have lower power reliable moves than Special (Punches vs beams/bolts/pulses) but their high power moves tend to have 100% accuracy with a downside (Close combat, superpower, recoil), wheras special moves have lower accuracy with an upside (Thunder/Fire Blast etc) or even when they have a drawback, still have imperfect accuracy (Overheat etc).
This plays into physical attackers getting their big hit off regardless wheras special attackers risk not landing a bigger hit at all.
All bar one of the priority moves are physical, the importance of which cannot be understated.
There's also weird little things, like physical sweepers from gen I and II tended to have low special Defence, but high Defence. Thus why the Asssault Vest boosts Special Defence and not physical defence.
TL;DR GF would have to give more things nasty plot + rebalance moves for special nerf move to be balanced