Will be interesting to ser hon them fare post group stages. Haven't watched any placement games but in the streams featuring Soviets I've watched they've looked pretty solid.
Most of the streams are top 10 players versus whoever they get in an automatch. The skill difference is usually enough that the faction doesn't matter. In the GCS, where they play mirror matchs for placement, there are still some mismatches but most of the time the skill difference isn't as great and Ost or OKW wins both.
After the placement matches, I'd expect that top seeds win with Soviets through the first couple rounds so the Soviet win rate would go up. After that, I'm not sure. If I was going to make a prediction, I'd bet it ends up at around 30%, assuming that top players keep using it. I'd also bet that most of the players switch to playing USF and the win rate ends up around 50%, with USF underperforming against OST and roughly equal against OKW.