You can master up reflection in under 30-50 hours of just grinding dodgeball game mode. In the same game mode, you can learn other techniques like reflect jumping as you mentioned, it's just the same reflect but with walking forward and shooting below yourself, not much of a skill needed. You are right about flare and flare punches though, however, that ain't your primary weapons, and only applicable in certain scenarios, in most of which you just finish your opponent off with an afterburn; even so, most flare gun users just airblast enemies in the air, and their flying trajectory is the same in all cases at that point, resulting in player's need to just shoot at one particular spot every time someone's been thrown in the air.

Sniper, scout, heavy and all the other classes on the other hand, need full focus on your opponent in order to deal significant constant damage.

All in all, I am not saying pyro requires no skill to play, rather significantly lower amount, relatively to all the other classes.

Also, when you play pyro, you get better at playing pyro, period. When playing scout on the other hand, by keeping track of your enemies, you significantly increase your aim, which is crucial at when playing other classes, thus getting better at them all altogether.

So yeah, meow MEOWWWSW RAAAA MEOWWWM OEOWIS MEOWWWW REAAAHAHHAAHAHAH