I never understood the appeal of competitive TF2, personally. The game was never designed with competitive play in mind, so getting it to work is a nightmare. Some classes are hilariously weak, some classes are way too strong, some weapons break the system and need to be banned, so on and so forth. Outside of a casual environment, TF2 doesn't really hold together well.
I think another issue is that there are only so many classes that have immediate fire power or utility. I refer to it was Ready Set vs. Wind Up gameplay.
Classes like Engineer, Spy, Sniper are although incredibly useful, require some sort of time table to work with or immense skill that revolves around precision. Engineer takes time to set up his things and upgrade, Sniper has to crouch strafe waiting for full charges, and Spy has to hide and shuttle around invisibly and pray to Hale himself if he doesn’t want to be vaporized. These are Wind Up classes.
On the other hand, Demo Man, Soldier, Scout, and Medic are Ready Start classes. No matter where you are on the map, you’re vital to victory by filling a niche or even having high levels of chemistry. It’s why you see Medics Naturally gravitate before Soldier and Heavy before going onto someone else. It takes quite literally less then 20 clicks between the entire team to start a heavy bombardment offensive with high mobility, damage, survivability, and kit variation. They’re specific enough to fill a job but have enough wiggle room to shake up what weapons they could use.
The Wind Up classes have no such luxury. They have a gimmick with very little variation, and even with variation, is often more detrimental then not, and they default back to stock. Against Ready Start classes, you simply can’t prepare. It makes those 3 classes rare to see, harder to see used well, and hardest to see not be the first to die even when played well.
EDIT: Sorry for Tisming out, I just hold a lot of love for this game despite it’s... unsavory audience at the moment.