I will be supported and in same time US arty is not so accurate so arty vs arty and OKW wins.
It needs to have less dmg or worse accuracy.
Its so expensive that if okw player decide to buy it, he will be even more susceptible to ally blob. Its fine as it is, just look on some replays, not so many people buy that isg anyway. I tend to get one from time to time and it works wonders when enemy charge mindlesly at me with bunched up rifle blobs (like 5 squads grouped together). Then for sure it will kill stuff, maybe not the units it was shooting at but the ones arround. But thats not the problem with isg, its just a problem with US player who clearly lack some common sense.