Lets discuss why the Pyro is OP:
Can light Spys on fire
Has the ability to remove sappers
Can use a detonator to jump higher
Has the Reserve Shooter and the Degreaser, which the weapon switch speed stacks.
Has the Reserve shooter and a main weapon that can send opponents flying, making it OP.
Has a melee weapon that allows it to go faster, and also gives health.
Can deal massive damage to opponents who are in water, which would normally be a safe place.
These are really bad reasons as to why the Pyro is OP. I agree that he is very OP but these reasons are terrible.
The Pyro is a counter to the spy, so yea...
The Pyro being able to remove sappers goes with the first point
The Soldier, Demo, and Scout can all jump higher
Fast weapon switch in itself isn't OP at all
The Reserve Shooter is also for the Soldier, who also has a weapon that can send opponents flying
The Soldier has a melee weapon that can make him go faster, the Half Zatoichi also gives health so...yea, also the Powerjack's extra damage allows the Pyro to be 1 shotted by Snipers and easily killed by many classes
Practically every class that can deal damage can deal damage in water, if you think you're safe in water you're very mistaken lol.
The main reason the Pyro is OP is because of it's versatility, it's got something to deal with literally all of the classes, not just effectively but quickly, lots of other classes have this pleasure as well but unlike the Pyro there's a trade off, for example the Natacha can make dealing with Scouts a breeze, the trade off is you're going to severely damage your output vs other classes, the Pyro can use the Degreaser, Flare Gun, and Axtinguisher to effectively deal with any class except Demoknights(Targe n Charge) which can be airblasted away and are easy to escape, and other Pyros.