I'd be more interested in more of an airblast range decrease and pushback decrease when pushing other player units with the degreaser airblast, but keep the airblast reflect range for rockets the same. It encourages close combat, well then you should get in close. This would allow people to keep their quick switching while giving the degreaser a notable performance flaw while using it, which is how all non-stock weapons are supposed to be, getting something for giving something up.
Keep the ammo, keep the mini crits. The ability to push back another player from a considerable range (longer then the actual flame in hammer units) and switch near instantly is the relative problem. You're not giving anything up for using the weapon. Afterburn damage and flame damage are negligible because that is not a pyro's main source of damage, like pointed out again and again.
TL;DR: The degreaser needs some sort of side downgrade that makes sense to counter-act the quickswitch, otherwise there is literally no reason ever to use any other flame-thrower, which Valve does not want.
Also, pyro is the only class that never recommends viable item builds outside of the one-two combo of the degreaser. That in itself is a problem, because that shows there's a weapon monopoly.
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Moving on, Soldier secondaries need to be seriously looked at. There is no reason ever to use anything outside of the shotgun or gunboats, and even sometimes not even the shotgun (in highlander). Every other secondary needs a buff to them to compete. Why use any of the banner secondaries when you can jump more? The bison is a pretty powerful weapon too, but the speed of it is what gimps it to not being used over the shotgun.