It sounds like the soviet teams you are running into are using some really strong combined arms and you might be succumbing to sniper rage which happens to a lot of players. Use the german sniper to pick off the supporting units and remove the support which will force the snipers to either retreat or they will be left out to dry.
The heavy tanks come in at about the 19-20 minute mark and I'm surprised that you didn't have any thing out at that time to at least deter an IS-2.
Send me the replay and I'll take a look at it. Unfortunately the devil is in the details with this game and it's incredibly difficult to describe all the engagements that occur in a single match.
We have experimented with snipers but it's tough to keep them alive with sov snipers - essentially the two-man sniper team makes them a hard counter to your sniper, and 6 man soviet squads make them much more resilient to sniper fire than your people are. It's a high risk counter for enemy snipers, imo. It was somewhat effective when Shocks were at 1cp but I don't know how viable it is now, at least at our skill level.
Don't have the replay, it was several games ago and I only occasionally save them. From memory it was an unusually intense early game and they didn't get any big heavy hitting vechs until the IS comes out. My partner got an ostwind because we were in danger of being overrun and I had a couple of AT guns, but shit happens. Your AT guns can't really be front line units, and the IS2 has quite good range. Once your squads start exploding its all downhill from there.
I know what you're saying about combined arms. They do have good combined arms play, and we have good unit combinations too. We're only in the 80 game range I think, but we're both 600+ hour vets from the first game. There are no obvious "oh duh use this one unit and everything falls into place" fixes - we weren't having major problems until this new patch hit. Then again, we're both working men now and don't have much time to practice new strats. We'll play 4-5 games a week maybe.