Just to play devil's advocate here, in Space Hulk using the flamer leaves pools of flame for 1 turn. You use it to cut off access to specific corridors.
Sooooooo... why didn't they just use the visuals for the Melta instead of particle-effects? No. Wait. Let me guess. A programmer trying to make it work his way despite what others say and then it doesn't work and gets scrapped and there's no time/money to give it a second try. EDIT: That happened once for a Mechwarrior-game. Everybody knows that Mechs don't have force-fields. But the programmers coded force-fields anyways and put a lot of effort in them to make them look good. And then they were disappointed that they couldn't add force-fields to the game because of lore.
They have stated that they are considering making a unique hero with a flamer. That is honestly the best choice with what we have currently.
I believe the issue was having too many flamers in the match at once risking destroying everything. That's why they were looking into vehicle heavy flamers, because there was a limited number of tanks at any given time and that that number was much smaller than the number of players.
if u want u have to remove allies to allies kill. we are already killing our allies with bolters and meta. 98% player that use flamers will be kick from game