Well Relic didn't say they thought Sniper and Car was fine they just didn't mention it at all. That's not the same thing since they hardly mentioned anything about upcoming balance.
With that said, the I feel Sniper Teams should have a greatly reduced accuracy when firing from the car. Maybe like 30% of shots hit from stationary and less when moving, or something like that. Seems like that would fix the issue.
In 1v1 if they open up with a Tier 1 start and you see the M3A1 you can go 4 T1 units into T2 -> Upgunned car right away and that usually will deal with it before Guards come out.
I had a 1 hour 40 or more game in vCoH. I was Brits on Langres and he was PE. I firmly had the north VP and the centre locked down. He kept running in and scorching the centre VP non-stop. I couldn't quite hold off each push due to pop cap and the last 30 minutes of the game was me repairing the point and him scorching it over and over. Then he quit.
I find the best way to use it (contrary to a higher post) is to use the attack ground command rather than the barrage ability. The barrage takes a long time to recharge and to begin. The attack ground allows you to retarget quickly. If you do stick with the barrage make sure you use the attack ground command while the barrage is on cool down for new targets.
It's also map dependant, and dependant on your opponents play. If they are going all grens then it's probably best left to the side. If they have MG's and mortars go for it.
It's expensive and slow to fire, which means if you've gone tier 2 you have a more tactical option in the 82mm. Only go the 120mm over the 82mm if they are blobing heavily, camping, or building lots of bunkers.
If you go tier 1, then it's a great way to get a mortar without having to build tier 2.