Lack of attention to detail in regards to vehicle balancing. Some vehicles got over buffed and over nerfed when they just needed slight adjustments. Moreover, some over powered vehicles were not addressed such as the T26e5 and Lowe which clearly need changes.
Overall, I think 9.17.1 is reinforcing the idea of power creep. I'd prefer the balancing department focus more on fine details rather than giving into people's complaints and the marketing department who are both biased towards unbalancing the game.
WG Marketing Department
-How can we make lots of money?
-I know! We can introduce new OP premium tanks every month. Then buff all the non-premiums later to give the appearance that our game is balanced and not Pay2win!