They’re basically telling people what is worth more instead of letting the community decide what cosmetics are better than the others
That's not true, some prime examples are the well-wrapped hat (assassin grade) and the airborne attire (mercenary grade), the latter is the more expensive of the two, and the community decided that.
Also, whose to say the jetpack won't allow for flanking. If anything, it gives the Pyro more flank roots as he doesn't have to follow the already made ones, making it much harder for people to find him. I'm assuming the weapon will work similar to Pharah's jetpack where you hold to ascend, release to descend and there's a limit to how you can use it so as long as you're not being wicked stupid and propelling yourself into the air as high as possible, I can see this weapon having a lot of potential.
As for the community crap that you keep babbling on about creeper, the only thing valve can take from the community is weapon designs and maps. Also, why not take that stuff? The community voted for them through Arms Race III and the workshop so it's what they want making this nothing short of a smart business approach. I'm sure overwatch would thrive even further if it's community had more freedom to improve the game.
Now, for weapon changes, what do you mean "one class every few years"? You obviously don't play the game because the last two campaign updates and the proposed changes for this one are directed towards most, if not all classes. Not a single class has gone without a weapon buff / nerf post Gun Mettle and while a few of these changes were questionable (like the bison), a lot are better than their prior stats.