Well, we have Ernst Gaede, Z-39, and Z-23 that can all mount 150mm guns
Edit: I wouldn't mind seeing some monitors or similar ships at lower tiers or in a special mode, even for April Fool's though.
German battleships have a turtle-back armor scheme which makes citadelling them harder. Most UKBBs have citadels under their waterlines which can also be hard to hit. You can view a ship's citadel in the armor viewer in port. If you want to see just the ship's citadel, you can disable the other armor types by clicking them:
Queen Elizabeth's main turrets traverse slower than Warspite's. She also does not have the tiny 550m turning radius that allows Warspite to pull off some crazy dodges . QE does get about 1km more firing range, better AA, and a bit more health though.
You can repair your ship's rudder by using the Damage Control Party consumable. Steering Gears Modification 1 and Steering Gears Modification 3 also reduce the repair time for your ship's rudder. You can also take the Last Stand commander skill to use your rudder and engine when incapacitated, but with a penalty.