To be completely honest there are probably many of these stat idea discussions, however I thought I had some interesting ideas for a flamethrower that are all connected to one item. This list is very long but has many of my most brilliant ideas.

IDEA 1. The "Damage Loss Over Time" mechanic

We have all met those "W-Mouse1" pyros and that gave me the WM1 counter idea that instead of having a constant and steady damage output, the flamethrower could start with high damage for 2 or so seconds, but after 2 seconds of holding down Mouse1 (fire) the flamethrower's damage changes from high to weaker and weaker over the course of another 3 seconds until it is considerably low. As the damage gets lower the flame dies down as an indicator. A very brief release (exactly .7 seconds) of Mouse1 would cause the damage to be reset to its default high damage. Hitting Mouse2 (airblast) while Mouse1 is already being pressed would automatically trigger an airblast without the release of Mouse1 and would last long enough to reset the damage so when the airblast is over,if Mouse1 is still being pressed, the high damage fire would automatically start.

For those who still don't understand the concept, I have made this damage over time graph that DOES NOT account for the effects of afterburn.
This graph demonstrates a situation where one pyro using every stock weapon and under no mini-crits or critical hit inducing effects except for the Afterburner is holding down Mouse1 on another entirely default loadout pyro who is under no effects and is afk at point blank range in a server with only the 2 pyro's and a testing map that is a square box with no hazards.

~ = time interval of .75 seconds where the player releases the fire button or uses the airblast

TIME IN SECONDS 1 2 3 4 5 6 ~ 7.7

DAMAGE PER PARTICLE DURING SECOND 7.5 7.5 6 4.5 3 3 0 7.5
(a particle is every time your hitsound goes ding)

This system would encourage players not to hold down the mouse button for damage but instead tap Mouse1 in 2 second intervals or hit airblast whenever needed in order to use the weapons damage bonus. If a player decided to hold Mouse1 down long enough for the damage to decrease two things would happen, the first being that ammo required to use the flamethrower and the airblast would decrease by 50% in order to insure the player does not run out of ammo from holding Mouse1 down, from constant airblasting to reset the flamethrower's damage, or from using idea 2's concept. The second thing that happens from holding down Mouse1 happens to be idea 2

IDEA 2. The "Warmup Afterburn" Mechanic

Before discussing what idea 2 does it is important that I make the following action easy to describe in one word. Holding down Mouse1 for more than 2 seconds, according to everything already stated, is ammo efficient for the fire and the airblast in order to perform non-costly damage resets allowing for the player to hold Mouse1 for a long ammount of time but at extremely low direct flame damage. performing this action will now be refered to as "overheating"

Idea 2 is that setting a player on fire while overheating will cause that player to experience a much harsher afterburn with a 12 second duration and 3 damage per tick(ticks are damages done every.5 seconds of afterburn). Mini-crits boost the duration up to 15 seconds and increases the damage by 35% ,and crits bring the duration down to 10 seconds but push the damage per second of afterburn to 5 damage per tick and increases damage times 3.
The downside to this mechanic is that the flamethrower cannot afterburn while it is in its initial seconds of high damage. Players must wait for the damage to go down before they can cause an enemy player to feel the effects of this weapons amplified afterburn.

IDEA 3. The "Intake" Mechanic

My third and final idea is to help make the airblast a bit more unique. while the weapon is not overheating the airblast sucks in players in order to apply the initial damage. When the weapon is overheating the airblast has a strong knockback away from the player.

All three ideas give the weapon two playstyles. Run in offensively using the increased damage and applying the airblast before the weapon overheats in order to maintain a cycle of high damage followed by a suction blast to keep your target near you. The other strategy is to pull an enemy with the intake, then use the high damage to weaken them, then when the damage lowers, apply the weapons harsh afterburn effects on the already weakened opponent, and blast them far away using the overheated super airblast and hope you kill them with the afterburn.

Whoever read this whole thing I solute you. Many of my ideas were not simple to explain so I hope it is easy to understand and not too long to read through, and if the creator of the item reads this i just want to say I really hope the weapon gets added with these mechanics to spice up the way people play Pyro.