Either Bisko or Tirpitz will be a premium ship, that's for sure because they're both ship of the same class, you can only unlock one of them in the tech tree. And not just you, even me who play a bit more regularly still struggle to get past Tier 6 (I think I should reach my Fuso again today due to 2x EXP during the weekend celebration for Wargaming), the exp required now and the exp gained nerfed at lower tiered ships is definitely making it harder for you to progress, I won't have mind that after OBT when the game officially launch because then I would keep everything, but even now whatever I work towards will get wiped anyway, so that's why I haven't been bothered to unlock my Myoukou/Mogami yet (because I know they're my favorite ships already from CBT and Atago is basically an enhanced Myoukou), I'm trying to work on my DD and BB (I would like Shimakaze and Yamato when it comes out of OBT), CV wise I'm not quite sure, as much as I like Shoukaku onwards, the first few tiers are just currently in such a sticky situation (especially if you encounter a USS CV) that I'm really annoyed at playing IJN CV at the moment.
