I still feel T3 is extremely viable even if your opponent goes T4 and pushes out SU-85's. That said, I typically rely on PAK's to push my opponent's armor back. An Ostwind and a few Grens backed by a Pak or two can be a very valid thread to a T4 Soviet player.
Just my personal opinion of course, others are welcomed to disagree.
http://www.twitch.tv/daveschro/b/439041081
Skip to 4:40 until the end.
When this happens do you understand why people get upset? There are really debilitating instances like this in this game that turn the game for no reason. The panzerfaust bug can end a game when it does no damage to an m3. I've had that happen to me endlessly, and if I remember to catch it again I'll post up the video but come on. This isn't like some hidden bug that never happens. All you have to do is play the actual game to see how crippling some of these things really are. Yet the top priority seems to be extinguishing strafe and making it so Panzer 4s can't kill a sniper in the open field...
About the actual bug - There seems to be a target priority shift when the 76 moves to artillery mode that causes the pak to target something else (the engis in this instance). Also, why can't it shoot in the beginning of that engagement? A pole? Really?