Thanks to Babykim, EU
From a video by getfun
the developer JamesWhite mentioned in his weekly stream that:
1). The Anshan and Arizona have the highest win rates in the current ranked season (RU server). They are followed by Atago, Takao, Bismarck, Cleveland and Benson.
2). The WG plans to remove some premium ships from the shop because of a general over-saturation of games with premium ships. A hot candidate for removal is Murmansk.