1. players have been trying to reach the IS-4 before patch for the last month.. for those who succeeded, they will have a free tier 10, those who didn't.. too bad.
2. the dynamic of medium company battles is about to change dramatically with the death of the KV-3 (being moved to tier 7) for those that researched and got the KV-1s, their day of vengeance is here as it is now the top tier 6 heavy.
3. the dynasty of the KV is dead, no longer will it rule the tier 5 circuit. BDR and PZ owners will have their revenge as they are now more powerful than the KV-1. and expect to here whines about how the churchill is overpowered in tier 5, as the KV no longer can own it and it has little issues dispatching anything its tier and surviving, making a premium tank equal to, or superior to it's tier 5 counterparts.
4. this patch marks the most likely death of most of the german tier 10's for a while (until the german gun revamp).. people don't believe me, but you will see for yourself, the new gun on the IS-8, IS-4, and ST-1 really does have very little issues penning those monsters and people running the e-100 and maus will get tired of being nothing more than free experience for another tank.. considering any other nation's tier 10 fills the slot the german 10 does better.
so in a sum, it is a d-day of sorts, this patch will dramatically change the playing field in a lot of ways, for some, it will be relief.. for others.. things just got worse.