Not sure why people think it's a "so-so" or mediocre ability. You make a push and slap this ontop of it and it wins literally any armor engagement.
When was the last time you tested this ability?
It is very strong. This is basically a "pay muni to roll over the enemy" ability. Wrecks armor very well, while suppressing everything. The only counter is AA, which is OK to build it team games, but a debatable investment in 1v1, imo.
So for the muni you get vehicle killer and infantry suppresser. Pretty much a deadly 'propaganda' because it forces a mass retreat.
When was the last time you tested this ability?
It could be bugged, but I used it twice in two games, with sight over armour and infantry, it did nothing. Planes flew in, I had complete sight with stealthed jaeger.
Is it possible it is not working?
As a Sov main, I run Armoured Assault and Advanced Warfare since the 4ppsh cons on last patch, I don't play large team game so multiple schwerer not a problem for me, and the IL-2 Loiter is amazing against infantry, and especially at guns to support an armoured push, it is amazing to me even for 200. I miss that it also no longer kills tanks too though