If anyone would want to change barrage without removing it or making more expensive, I would have rather see it shooing like a JT. So at least cover and other blocks, would requre you to possition your zis.
In any case, aurgument that soviets dont have easy access to nades, thefor they need Barrage is somewhat true, honestly soviets having grenades would have been much better.
Unlike nades zis pretty much forces any support weapon to relocate like instanly, paired with your attack, you are able to breach enemy defences with much less efford then a player who has to flank with multiple squads and throw nades.
Not to mention, that stock soviet mortar is still shit, which is tecnically supposed to be way to counter support weapons and deffences.
The squads that cone with nades do force you to move your team weapons imo. The zis does a intial chunk if damage the follow up shot land all over the place. You need other units to follow up here a lot of the time.
Look at pgrens, they have good mid range dps they have a very power nade that can be trown at about that range. They do need to get a lot closer but they dont need follow up persee to get the job done.
The soviet mortar i agree is not that great. Io its barrages are not up to snuff. If that can be improved somehow, mainly response time. Flare could go vack to vet 1.