Interesting.
I actually saw the ability used for the first time in a few years yesterday, in a match between GiaA and Jimmy. The incendiary bombs landed on two AT guns, one had 4 crew members and 40% hp total, the other had 2 crew members at full hp. The incendiary bombs weren't able to finish off a single crew member. GiaA did respond quickly by reversing them out of the flames, but they were in there for at least 5 seconds not receiving much damage.
I would expect that since the Soviet version is extremely lethal but Ostheer does very little. Think one need to look at all incendiary weapons and make some changes (think is mostly the DOT that is different).
As far as I can remember ostheer mortar ΗΤ are far less effective vs emplacement than Leig. Funny thing is that the pit can actually destroy the MHT since it can easily cause AOE damage.
It still wouldn't fit Storm Doctrine. That said, adding them to Schrecked Panzergrenadiers would be a good addition for Jaeger Armor and would be fair if the commander gets toned down in the 2 ways suggested (no Spotting Scope for Elefant and Stuka Dive Bomb replaced with AT strafe pass).
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Well I mostly pointing out that Riegiel could use some changes.