Stats can be hard to interpret. Some tanks have better stats due to the better players playing it. Some tanks seem to get better MM. I have medium tanks of the same tier with very similar paper stats, yet notably different W/R for each, etc. The T49 is one of the most difficult tanks to play, which is why a higher percentage of the games played with it are from experienced players. It is a one shot kill for some tier 4s, and quite a few tier 5s. Get into the frequent tier 7 battle, and this baby can be killed in a one shot splash (or by having a turret pointing at it). And for goodness sakes, don't hit any bumps going too fast or you lose half your crew and 50% of your hp.
I like playing mine and have decent results from it. However, I like to judge whether a tank is OP from facing it rather than driving it. And when facing it, I have no fear and enjoy the one shot kill. I agree with the previous comment, there are many more tanks that are OP that need "rebalancing" long before any time should be spent on this little ole tier 5.
At this point, I have had so many of my non-Russian tanks nerfed to oblivion that this will not either surprise me or effect me much. I will just have to take out the KV1S and go on a one shot rage!!!