I've lost KV-8 to two PGrens and a Panzer 4...to me it seems like it burns the same as the FlamerHalftrack,which surprisingly or not took out 4 of my Conscript squads in mere seconds before any of them managed to throw a grenade...
My point being both KV-8 and FlameHT burn the same,why nerf just the Soviet one which doesn't come fast as the FlameHT?
This is just my opinion so don't hate,for me they all burn the same 
Firstly, the damage dealt is entirely different, as well as the cooldown, reload times, and fire-on-the-move capability. In all regards the Flame HT is weaker.
Secondly, they both come on entirely different platforms. The AT Grenade has guaranteed penetration on a Flamer HT whereas a Faust does not on a KV-8. With the increased damage on the AT Nade, it makes it entirely possible to take down a Flamer HT with some well microed Conscripts.
In addition to that fact, the general durability is cheaper and the timing is off. In the time I have a Flamer HT out, it is entirely possible for the Soviet to already have a sufficient AT counter in place - a ZiS or Guards Rifle squad.